News from Rohde & Schwarz

New test technology for module production

Digital monitoring direction finders for HF to UHF

ecoTV: solid-state transmitters set the pace in terms of economy

150 It is with deep sorrow that we say a last farewell to the highly esteemed senior partner and co-founder of our company

Dr. phil. nat. Dr. E. h. Hermann Schwarz

who passed away on 10 November 1995 at the age of 87.

Executive Board, Company Management, Employees and Workers’ Council of ROHDE & SCHWARZ GmbH & Co. KG

Dr. Hermann Schwarz, a pioneer of test and communication engineering

“60 years Rohde & Schwarz – contributed to his decision to study they laid the foundation for the compa- 60 years of a life dedicated to Rohde natural sciences following grammar ny Rohde & Schwarz, an international & Schwarz” – this is the heading school in Nuremberg. He began his enterprise, which today employs more Dr. Hermann Schwarz chose for an studies of physics, mathematics and than 4,000 people and is still inde- article in “Zeitzeichen”, the inhouse geophysics in Heidelberg, continued pendent. magazine for Rohde & Schwarz in Munich - the time he spent here was employees, on the occasion of the certainly one factor in his decision to While R&D in the laboratory – with a company’s 60th anniversary. Now, set up business in this city a few years focus on impedance and dissipation- only two years later, this life has later – and finished in Jena, where he factor measurements – still made up ended. Dr. Dr. E. h. Hermann Schwarz attended lectures by Prof. Esau and the bulk of Hermann Schwarz’s work passed away in his 88th year on the Max Wien, met his future friend and in the first few years, he was also from evening of 10 November 1995. partner Lothar Rohde and received his the beginning responsible for organ- doctorate in 1931. Finding a job was izational and administrative tasks. As Born in the old free city of Nördlingen very difficult for young physicists in both the staff and premises of the en- in Swabia in 1908, he was to live a time of economic depression, so terprise expanded, he had to dedicate through all ten decades of the 20th the two friends stayed on at university more and more of his time to com- century, turbulent and history-laden as for two more years. The contacts to pany policy with regard to personnel they were. His youth in his hometown industry they made there, however, and management, which on the other and the holidays he spent on the farms encouraged them to set up their own hand encouraged his solid talents of relatives in the nearby country were enterprise in Munich in 1933. With for business. It had been his idea, for the basis for his life-long and deeply the Physico-technical Development instance, that designs developed by felt love of nature, which probably Laboratory Dr. Rohde & Dr. Schwarz Rohde & Schwarz should not be sold but produced by the company itself. expansion of the group on both the had evolved from his early love of Acquisition of the premises at Tassilo- domestic and international market, in nature and which he cultivated enthu- platz in Munich in 1937 again showed particular by building up a large sales siastically thus finding recreation from his grasp of future perspectives. As network in Europe, Asia and America. the stress of everyday work. the price for the new premises was This gave him a chance to get to know almost twice the small company’s other countries and peoples and to Understandably, his invaluable con- balance-sheet total of the previous acquire friends around the world. Just tribution to society was officially year, this venturesome step was a true like his employees, they admired him recognized. As early as 1959 the entrepreneurial decision which can be for his charm, honesty and sense of Technical University of Munich ap- seen as the next milestone following social responsibility, but also for his pointed Dr. Schwarz honorary sena- the start of the company. The company ability to formulate cogent arguments, tor. He was also a commercial judge was now ready for further growth, for his extraordinary knowledge of for many years, and in 1971 became and at the outbreak of World War II history and almost endless supply of honorary consul of the Republic of already had 100 employees. For quotations. Iceland. Besides other decorations he many major firms in the communica- was awarded the Bavarian Order of tions sector R&S was the regular sup- Hermann Schwarz showed again Merit, the Commander’s Cross of the plier of the test equipment they needed that he was very much aware of his Order of Merit of the Federal Republic for production. As a consequence, responsibility for the future of the com- of Germany, the Medal for Contribu- R&S soon ran out of space, so the pany by making provisions for suc- tions to the Bavarian Economy and the Tassiloplatz building had to be ex- cession in 1971 in order to be able Golden Medal of Honour of the City of tended and new buildings added. In to cope with any possible course of Munich. For his exemplary industrial those years Hermann Schwarz was affairs or risks. After his son Friedrich policy he received the Seal of the City confronted with difficult decisions such had completed his education and train- of Memmingen in 1984 and became as the city council’s plans to relocate ing with excellent results, Hermann honorary citizen of Teisnach. It was the company or the need to find new Schwarz appointed him to the Ex- particularly gratifying for Hermann production sites after air raids had ecutive Board, allowing himself to re- Schwarz to become honorary doctor caused damage. These questions were duce his personal involvement in man- of his former university in Jena in 1991 of significance for the very existence agement tasks and hand over respon- after German reunification. of the company and its employees, sibility step by step. When he finally Albert Habermann who by then numbered several gave up Human Resources – his last hundreds. The partnership of the two field of work – he left behind an area owners was also put to many a test but of management that had particularly proved to withstand all difficulties. benefited from the extraordinary hu- manness of his character for decades. At that time, true entrepreneurial vision The fact that he always demanded was required to maintain one’s power very high standards of his own work of judgement despite all political and with people made him fit as a role economic problems. The same is true model. This was something his em- of the time of post-war reconstruction ployees could always feel; he inspired that followed, although it provided a their confidence by having confidence much more gratifying basis. The posi- in them. Throughout his life he com- tive economic trend was reflected in bined entrepreneurial leadership with the purposeful yet careful expansion humanist values and thus acquired a of the new plant on Mühldorfstrasse father-like aura for many in the com- in Munich. It was at this stage that pany. Employees and friends always Hermann Schwarz could explicitly put treasured his fairness, his deep knowl- to use his entrepreneurial flair. The edge of human nature, his love of life, decisions to set up Messgerätebau his tolerance, his charm, which was GmbH in Memmingen, the R&S plant visible through an often patriarchal in Cologne, sales offices in various surface, and his exemplary esteem for locations and later the production family ties. These qualities enabled plant in Teisnach in the Bavarian For- him to make friends not only in his im- est are further milestones that give mediate surroundings but also among evidence of Hermann Schwarz’s in- people he met pursuing his hobbies, itiative. Another important area was namely hunting and fishing, which Number 150 1996/I Volume 36

In RF measurements, network analysis is the most important task beside spectral analysis and test signal generation. Rohde & Schwarz has launched a complete family of top-grade vector network analyzers, namely entry-level model ZVRL, standard model ZVRE and general-purpose model ZVR – in short, the perfect solution for any requirement and any budget (see article on page 6).

Articles

Dr. Olaf Ostwald; Vector Network Analyzer Family ZVR Christian Evers To the heart of the chart ...... 6 Dr. Lothar Tschimpke LaserVision System LV1 Optical insertion testing combined with classic board test ...... 10 Klaus Kundinger; Universal Test System TSU Dr. Lothar Tschimpke Versatile test platform for production and service of electronic modules...... 13 Michael Lehmann; TV Monitoring and Test Systems TS6100 Gerhard Strauss Video and audio parameters of TV transmitters all under control ...... 16 Josef Wolf Spectrum Analyzer FSE with Option FSE-B7 Vector signal analysis – indispensable in digital mobile radio...... 19 Franz Demmel; Ulrich Unselt; Digital Monitoring Direction Finders DDF0xM Dr. Eckhard Schmengler State-of-the-art monitoring direction finding from HF to UHF ...... 22 Hans Seeberger Solid-state UHF TV Transmitter NH500 The new reference for TV transmitters: ecoTV...... 26 Franz Demmel; 150-W HF Dipole HX002A1 Axel Klein The antenna for reliable shortwave links ...... 29

Application notes

Albert Winter Test signals for digital television ...... 32 Michael Manert; Wilfried Tiwald BER measurements with Base-Station Test System TS8510 ...... 34 Martin Schlechter Loudspeaker measurements with Audio Analyzer UPD...... 36 Mathias Leutiger; Daniel Schröder Signal Generator SME for tests on ERMES, FLEX and POCSAG pagers ...... 38 Otmar Wanierke Interference analysis in digital mobile-radio networks...... 40 Martin Flach Longterm monitoring of digital serial video signal using Digital Video Component Analyzer VCA ...... 42 Richard Finkenzeller; Ernst Polz Measuring all TV RF and video parameters for the first time in a compact unit ..44 Manfred Jungherz; Radiocommunication system helps Italian Peter Maurer customs authorities in coastal monitoring...... 46

Refresher topic

Peter Hatzold Digital modulation and mobile radio (I)...... 48

4 News from Rohde & Schwarz Number 150 (1996/I) Panorama

Hans Wagner Remarks on the future of radiocommunications ...... 52 Michael Vohrer Multimode Radiocommunication Tester CMD for GSM, PCN, PCS and DECT mobiles ...... 53 Michael Vohrer Low-cost Service Radiocommunication Testers CMD50/53 for GSM/PCN/PCS mobiles ...... 54 Thomas Maucksch CMD compact tester R4860 tests telephones of Japanese mobile radio network PDC...... 56 Dr. Andreas Waßerburger Gas chromatography for monitoring production processes in chemical industry ...... 57

Regular features

Wilhelm Kraemer Test hint: Installing directional antennas for microwave WLANs ...... 15 Reference: Matsushita relays in Audio Analyzer UPD measure the best of audio...... 25 Albert Winter Software: Software SME-K1 for programming the data generator of Signal Generator SME ...... 50 Prof. Dr.-Ing. Burkhard Schiek; Patent: Holger Heuermann Calibration method for network analyzers ...... 51 Newsgrams ...... 58 Information in print/Booktalk: Der deutsche Rundfunk...... 60 Press comments ...... 61 Werner Baumgärtel Final article: Rohde & Schwarz system support – there’s system to our service...62

For module testing in production Rohde & Schwarz relies on combining various test methods in a single unit. The wide spectrum of problems from insertion errors through to non-compliance with specifications is now mastered by one test system that applies the most appropriate test method for each situation. What has so far been impossible to detect by affordable electrical measurements can now easily be revealed by optical means such as laser and image processing. The customer’s benefits are high error-detection rate, short test setup time and large throughput (see articles on pages 10 and 13).

Imprint

Published by ROHDE & SCHWARZ GmbH & Co. KG Mühldorfstraße 15 D - 81671 Munich Telephone (0 89) 41 29-0 · international *(4989) 41 29-0 · Telex 523703 (rs d) · Editors: H. Wegener and G. Sönnichsen (German); C. B. Newberry, I. Davidson, G. Koranyi (English) · Photos: S. Huber · Circulation 100 000 three times a year · ISSN 0028-9108 · Supply free of charge · State company or position · Printed in the Federal Republic of Germany by peschke druck, Munich · Reproduction of extracts permitted if source is stated and copy sent to R & S Munich

News from Rohde & Schwarz Number 150 (1996/I) 5 Articles

Vector Network Analyzer Family ZVR of all models is further enhanced by accessories and options such as calibration and verification kits, three- port adapters or special firmware To the heart packages for frequency-converting and of the chart nonlinear measurements. The entry-level model, unidirectional Vector Network Analyzer Family ZVR with its exceptionally high measurement Vector Network Analyzer ZVRL, is for speed gives an entirely new view of aspects of RF circuits which cannot be forward transmission and reflection revealed by conventional analyzers. It has a wide dynamic range thanks to measurements which also provide fundamental mixing. An extremely large frequency range is covered by the inte- derived quantities such as input imped- grated bridges. Innovative calibration methods such as TOM-X, TNA and AutoCal ance, VSWR or group delay. ZVRL is ensure high measurement accuracy. especially designed for use in produc-

FIG 1 Network analyzers from ZVR family can 9 kHz or 300 kHz to 4 GHz depending tion environments and only requires rapidly and precisely handle different tasks simul- on the integral test set selected (FIG 2). simple calibration methods such as taneously – left measuring transfer function of bandpass, right simulation without additional PC. All models feature an IBM-PC compat- normalization and full oneport calibra- Photo 42 257 ible processor core with floppy-disk tion. Bidirectional Network Analyzer drive, hard disk, slots for options as ZVRE is ideal for general-purpose appli- well as external interfaces to connect a cations, as for instance in research and The ZVR family comprises the three keyboard, mouse and up to two addi- development labs where forward and models ZVRL, ZVRE and ZVR, each tail- tional monitors for the analyzer display reverse s-parameters of twoport devices ored to a different field of application and the PC screen. This ensures easy have to be measured. Unlike ZVRL, it (FIG 1). The common features of all analysis of measurement results, their has a test set with two bridges and an models are their ease of operation, professional documentation and effec- electronic switch for quasi-simultaneous lightning measurement speed and large tive networking within the analyzer measurement of all four s-parameters. frequency range that covers 10 Hz, or with other systems. The effectiveness This paves the way for the increase in

6 News from Rohde & Schwarz Number 150 (1996/I) Articles

The time for a complete frequency sweep is determined by the number with active test set of testpoints, the IF bandwidth and any averaging used. ZVR analyzers allow with passive test set any number of testpoints between FIG 2 one and 2001 to be selected. A linear, Frequency ranges with External Measurements option of ZVR family logarithmic or arbitrarily segmented sweep can be used.

The IF bandwidth can be set in half- decade steps between 1 Hz and 10 kHz measurement accuracy that can be ured values can be converted and dis- and also set to “full” (26.5 kHz). Digi- obtained with full twoport system-error played in various formats and easily tal IF filters are used and a certain num- calibration [1]. read off the large, bright, high-contrast, ber of IF signal samples are processed colour LCD (FIG 3) without operator by an internal transputer. With reduced Bidirectional four-channel Network fatigue. IF bandwidth, the number of samples Analyzer ZVR allows the most sophis- required increases and so measure- ticated, novel calibration methods to Measurement speed ment time becomes correspondingly be carried out. Unlike the three-channel longer for each point. As another trans- ZVRE, it has a second reference chan- The key feature of a modern analyzer – puter processes measurement data in nel after the electronic switch so that especially for applications in produc- the background while new measured it is able to carry out a variety of in- tion – is measurement speed. Quick values are being acquired at the next novative calibration procedures (TOM, measurements increase final test frequency point, this does not affect TRM, TRL, TNA, TOM-X) [2; 3]. These throughput and cut costs. Also, fast measurement time, which is 250 µs are characterized by increased con- result acquisition opens up applications per point for normalized measure- venience and measurement accuracy, which would be impossible for slower ments at an IF bandwidth of 10 kHz. mathematically exact elimination of analyzers. For example, measurements system crosstalk (see Patent on page 51) on GSM amplifiers for mobile-radio For full system-error correction, all four and are also especially well-suited applications. Thanks to high measure- s-parameters must be measured even if for in-fixture calibration. The new auto- ment speed, a key feature of the ZVR only one is to be displayed. Therefore, matic calibration method AutoCal [4], family, it is possible to perform five the electronic switch of bidirectional for which a patent is pending, offers vector measurements during a GSM Analyzers ZVRE and ZVR has to be maximum ease of operation and cali- pulse of only about 550 µs and so gain switched over at each frequency point, bration speed. Full twoport calibration completely new insight into the dy- the measurement channels in the re- of the analyzer takes less than 20 s with namic characteristics of GSM ampli- ceiver have to settle to a steady state just one through connection and with- fiers (FIG 4). for a second time, and the measured out any further manual handling.

The core of all network analyzers of the ZVR family is a fast synthesizer which provides crystal-accurate frequency changes in less than 20 µs. Its amplified output signal is taken to the DUT via the integral, model-specific configurable test set of the analyzer. Its transmission and reflection characteristics are measured by means of a two-stage hetero- dyne receiver which uses fundamental mixing and are digitally evaluated. The analyzers are equipped with a network FIG 3 of eight microprocessors specially de- Four-quadrant dis- signed to perform the various internal play of transmission tasks such as unit control, recording of and reflection characteristics of results, data processing, screen graphics filter with high stop- and remote control of the unit. Meas- band attenuation

News from Rohde & Schwarz Number 150 (1996/I) 7 Articles

values for the reverse s-parameters according to the specific characteristics Measurement accuracy have to be acquired and processed. In of the DUT. As well as the IF bandwidth, this case measurement time per point is the user can select any level and aver- Another point that should be empha- approximately 510 µs at a bandwidth aging factor for each sweep segment. sized is the measurement accuracy of of 10 kHz. In the case of filter measurements, for ZVR network analyzers which, for a example, this means that the maximum large number of typical applications, If even faster measurements are re- dynamic range in the stopband, the is much better than the rather conser- quired, there are two ways of boosting highest resolution in the passband, the vative specifications in the data sheet. performance: thanks to the full IF band- behaviour at stopband poles and filter This can be demonstrated by verifi- width (26.5 kHz) the measurement time transmission characteristics at spurious cation measurements. The phase per point is reduced to typically 165 µs frequencies can be displayed on the measurement accuracy of reflection for normalized measurements and screen at maximum speed in one measurements, for example, can easily 310 µs for measurements with full sweep. Production alignments and be checked. To do this, a TOM calibra- system-error correction. The fast mode checks which required cyclic measure- tion (Through, Open, Match) is carried additionally applies reduced settling ments can now be shown on one dis- out on the ZVR network analyzer. Port 1 times for the generator and the re- play. Of course, the segment sweep of ZVR is testport 1 and testport 2 is the ceiver. This cuts measurement time per is simultaneously available in each of end of a 50-cm test cable connected point to the extremely low value of the four display channels. Since the to port 2. The through calibration stan- about 110 µs for normalized measure- four channels can be displayed on the dard is very easy to implement by sim- ments, which means exactly five meas- colour LCD with tolerance lines and ply connecting the cable to port 1. For urements during a GSM pulse of separate pass/fail information, the dis- open and match calibration the stan- 550 µs. Measurements with full system- play facilities of ZVR analyzers have dards in Calibration Kit ZV-Z21 are error correction require about 235 µs still further potential for improving the used. After calibration, a female short per point in the fast mode while throughput of production testing and in- from Calibration Kit ZCAN [5], which still performing complete forward and creasing test depth without increasing acts as a verification DUT, is connected reverse measurements and parallel test duration. to the end of the test cable. The special system-error correction calculations. feature of this short is that its short-circuit The flyback time after a frequency The fast acquisition and display of plane exactly coincides with the refer- sweep is approximately 5 ms irrespec- measured values is supported by equal- ence plane, ie the edge of the outer tive of the mode and the number of ly fast data transfer via the IEC/IEEE conductor. Therefore, the phase of the testpoints. bus. For example, reading out a single reflection coefficient is expected to be marker takes only 15 ms, reading out exactly 180° over the entire frequency For very efficient, informative and fast the complete trace data comprising range. This phase offset of 180° is measurements, the characteristics that 401 points takes less than 60 ms. This entered via the offset menu to display have been referred to can be combined combination of fast measurement and the results, ZVR directly indicating its to give the special mode segment data transfer offers considerable scope own phase error. As FIG 5 shows, the sweep. Testpoints can be selected for rationalizing test sequences. typical error is less than 0.4°.

A calibrated network analyzer has another important system error which affects the measurement accuracy of both transmission and reflection measurements at twoports, namely effective load match. If the load port is not perfectly matched, multiple reflections arise between DUT and analyzer. If there are strong reflections from the DUT, measurement errors may be very FIG 4 large. Measurement uncertainties of Measurement of transmission (top) this kind must directly be included in the and reflection DUT specifications, in particular in the characteristics case of bandwidth tests and the assess- (bottom) of mobile- ment of shape factors. Effective load radio amplifier during GSM pulse match is easily measured after a TOM (approx. 550 µs) calibration by directly connecting the

8 News from Rohde & Schwarz Number 150 (1996/I) Articles

FIG 5 Left: phase errors of short-circuit verifi- REFERENCES cation (specification < 3° +0.4°/GHz); right: [1] Ostwald, O.: 12-term system-error correction [3] Eul, H. J.; Schiek, B.: Thru-Match-Reflect: effective load match measured (specification in network analysis. News from Rohde & One Result of a Rigorous Theory for De- <–30 dB) after system-error correction (TOM) Schwarz (1985) No. 108, pp 26 –27 embedding and Network Analyzer Calibra- [2] Engen, G. F.; Hoer, C. A.: Thru-Reflect-Line: tion. 18th European Microwave Conference, An Improved Technique for Calibrating the Stockholm (Sept. 1988) pp 909–914 Dual Six-Port Automatic Network Analyzer. [4] Rohde & Schwarz: Network analyzer. Ger- IEEE Trans. MTT-27 (Dec. 1979) No. 12, man patent application no. DE4401068 pp 987– 993 dated 15 January 1994 two testports and displaying the for- [5] Ostwald, O.: Precise measurements with Cal- ward reflection into testport 2 as shown ibration Kit ZCAN. News from Rohde & Schwarz (1988) No. 121, p 37 on the right in FIG 5. When compared with the specified value of –30 dB, it is evident that the measured effective load match is significantly better (<–50 dB) over a wide frequency range, so that in practice uncertainties caused by multiple reflections between analyzer and DUT can generally be ignored.

An example illustrating the value of the ZVR analyzers’ high measurement Condensed data of Network Analyzer Family ZVR accuracy, at low levels in particular, Frequency range is the quick and reliable search for with passive test set 9 kHz to 4 GHz with active test set 300 kHz to 4 GHz spurious resonances in filter crystals. with External Measurements option 10 Hz to 4 GHz Because of the high transmission loss Measurement time 110 µs/point of the specified π-networks for the test Dynamic range (with External Measurements adapters, the phase-zero crossings option and 10-Hz IF bandwidth) >130 dB have to be detected at an attenuation IF bandwidths 1 Hz to 10 kHz (half-decade steps) and 26.5 kHz (full) of approximately 60 dB. Thanks to the Amplitude uncertainty <0.05 dB high accuracy and dynamic range of Phase uncertainty <0.4° ZVR, this measurement can now also Calibration methods TOM, TRM, TRL, TNA, TOSM, be automated using marker evaluation TOM-X, AutoCal functions. The ZVR family takes vector Display 26-cm colour LCD network analysis into new applications Number of pixels 640 x 480 (SVGA) and meets the development and Remote control IEC 625-2 (SCPI 1994.0) or RS-232-C production requirements of tomorrow. Reader service card 150/01 Dr. Olaf Ostwald; Christian Evers

News from Rohde & Schwarz Number 150 (1996/I) 9 Articles

LaserVision System LV1 The LaserVision system can operate as a stand-alone although its main application is in extending the classic board testers by concentrating on faults that Optical insertion testing cannot be detected at all or only with difficulty by electrical means (eg combined with classic electrolytic capacitors with reversed polarity or incorrectly positioned me- board test chanical components). Through this limitation, LV1 offers a considerably With LaserVision System LV1 Rohde & Schwarz is extending its spectrum for more attractive price than vision and in-production testing of printed circuits. This system together with the in-circuit X-ray systems, some of which are test systems from Rohde & Schwarz allows greater test depth to be obtained in three to seven times more expensive. insertion testing than with purely electrical test equipment. Visual inspection is Although such systems can also ana- thus no longer required. Since electrical and optical tests run in parallel, the total lyze solder joints, they still mostly re- test time per board is reduced – an important aspect in production. quire a subsequent in-circuit test.

FIG 1 Combination of Board Test Workstation ployed in the production line after Measurement method TSA and LaserVision System LV1 for electrical the soldering station. It may be appro- and optical testing of printed circuits Photo 41 878 priate in some cases to test insertion The measuring unit of LV1 combines in prior to soldering directly after SMD a single unit optical image processing placement. LV1 is highly suitable for using two CCD cameras (charge-cou- testing a large range of lot sizes from pled devices) and a laser triangulation LaserVision System LV1 tests the in- sampling for quality control right technique for height measurement. The sertion of printed circuits in produc- through to 100% testing in mass two sensors together with the XY position by optical means. It is mainly em- production. tioning unit are moved over the board

10 News from Rohde & Schwarz Number 150 (1996/I) Articles

to be tested (FIG 1). Prerequisites for notch the marking line or slanted edge electrically in the majority of cases reliable results are viewability of the must be examined with the image-pro- because of the risk of overloading. board and reproducible contrast. cessing section. Suitable image resolution for different Operation component sizes is achieved by means Detectable insertion faults of two separate cameras. Components The two subsystems of LV1 are con- on the solder side are tested in a The vision system of LV1 detects: trolled and programmed from the same second run with the board turned over PC. The camera picture and evaluation • polarity of electrolytic capacitors or from below (in-line feed). window are positioned with the mouse (flat or upright mounted) or diodes, (FIG 4). Optical tests are performed ac- • SMD components (depending on cording to significant visual features. contrast), ideal typical Fault Pseudo-fault The rated values can be entered in the • parallel circuits (eg electrolytics respective boxes or learnt from the DUT parallel-connected with ceramic but can also be evaluated from a CAD capacitors), system. All settings are made via keys • small RF capacitors, coils, diodes and boxes; no special test language and protective circuits, need be learnt. Operation is practi- • wires, manual modifications, cally intuitive; programming takes typi- • displays, LEDs, LCDs, cally two to three minutes per com- • switches, jumpers, codings, FIG 2 Polarity test of upright and flat mounted ponent. To change between the test • mechanical components and their electrolytic capacitors program and control of LV1 during positions. program generation or debugging, the corresponding window has merely to The laser system checks: The image-processing section focuses be clicked. In the test mode, the two on simple features such as lines, notch- • presence of SMD components, measurement tasks run in parallel and es, markings and in particular with all • presence and orientation of ICs, are logged together. feasible spreads as they occur in pro- • switches, jumpers and mechanical duction: slightly displaced, turned or components. Economy tilted components (FIG 2). For testing the polarity of electrolytic capacitors for The effect of an undetected insertion Through the combination of electrical example, the position of the marking or fault can be illustrated with the aid of and optical tests the user can generate the positive or negative sign is taken as two examples. A wrongly polarized a reliably running test program in a a criterion. The permitted search area electrolytic capacitor in a power pack shorter time and thus obtains a higher and the separation from neighbouring explodes when the full voltage is ap- rate of fault detection than with purely components are defined by positioning plied in the system test and poses a con- electrical or optical testing. Using LV1 and reducing the selected window. siderable risk of injury to the operating together with a production test system Pseudo-faults occur when a component personnel (typically one in a hundred of families TSA [1; 2] or TSU [3] from is assessed as incorrect according to manually inserted electrolytic capaci- Rohde & Schwarz, the overall test time optical criteria although electrically it tors has reversed polarity). A missing does not increase in spite of the addi- behaves correctly, ie differing colouring overvoltage protection circuit remains tional tests involved and the greater or marking of components as a result of undetected in the standard test since test depth achieved. The standard changing to a new supplier. the components may not be tested electrical test (eg in-circuit test) and the optical tests run in parallel and the Components with low optical contrast results are not combined until the end. can also be tested with the laser by Taking a typical board with an in-circuit measuring the relative height with refer- test time of 15 s, during this time 30 ence to the board. Measurement errors ideal typical Fault Pseudo-fault to 50 components can also be tested arising from the curvature of the DUT optically – a sufficient quantity since can be compensated through reference only a small percentage of the com- measurements (FIG 3). Even the slight- ponents require the additional optical est height differences are measurable measurements. If an electrical signal is Test- so that not only missing components point necessary for the optical measurements notch but also wrongly polarized ICs can be (eg driving a LED display), the two detected through the absence of a FIG 3 Insertion testing based on height meas- types of measurements can be syn- notch indentation. For ICs without a urement chronized.

News from Rohde & Schwarz Number 150 (1996/I) 11 Articles

FIG 4 Programming of test on electrolytics using vision unit of LV1

LaserVision System LV1 can replace hidden through electrical testing alone. REFERENCES in many cases an operator carrying The fault detection rate is thus sub- [1] Tschimpke, L.: Test Workstation TSA for test- out visual inspection of the boards. In stantially higher than that obtained ing in electronics production and service. News from Rohde & Schwarz (1991) contrast to man as operator, no errors by electrical measurements although No. 132, pp 4–7 arise because of fatigue; for the Laser- only a small number of components is [2] Schröder, D.: Test Workstation TSAS tests Vision system the monotony of the tests tested optically. The pseudo-fault rate is complex boards in electronics production. is no problem. However, the operator is below 1%, which is considerably better News from Rohde & Schwarz (1992) superior to the machine in two aspects: than attainable using manufacturing No. 138, pp 4–7 he produces no pseudo-faults and can defects analyzers. Typical faults were [3] Kundinger, K.; Tschimpke, L.: Universal Test System TSU – Versatile test platform for pro- detect modifications adaptively and wrongly polarized electrolytic capaci- duction and service of electronic modules. assess them correctly. The latter cannot tors, slanted components or protruding, In this issue, pp 13 –15 be foreseen by the programmer or the non-coplanar or displaced connectors image-processing software. produced during soldering so that such boards could not be inserted into their The number of steps in testing is re- system. duced by the combinational test. This yields a benefit for the organization of The LaserVision system is therefore a the test run which is particularly effec- powerful and attractively priced supple- tive for fully automated production lines ment to board testers, with tasks in since each extra test station requires areas where electrical insertion tests space and additional costs are in- find their limits. The parallel running volved for the stop and associated tests reduce the overall test time for equipment. The objective is clearly: one boards and at the same time offer tester, one fixture, a single program greater test depth. and test-data acquisition, yet full fault Dr. Lothar Tschimpke coverage.

Experience Condensed data of LaserVision System LV1 Measurement technique image evaluation with 2 CCD cameras, Extensive experience has been gained laser distance measurement with the combinational test at a major Board size max. 520 mm x 330 mm supplier to one of the largest American Test rate typ. 2 to 3 components/s computer and instrument manufactur- Resolution Vision system camera 1 25 µm, camera 2 67 µm ers. Some 15,000 printed circuits (PC Laser system typ. 20 µm on component, mainboards) were tested per month typ. >0.5 mm on printed card on the combinational tester. The tests Option table without or with shift facility revealed mechanical faults for 5% of Reader service card 150/02 the boards which in the past remained

12 News from Rohde & Schwarz Number 150 (1996/I) Articles

Universal Test System TSU time. Moreover, the standard basic functions of a test system such as automatic fixture detection, auxiliary voltages for the fixture plug-ins, free inter- Versatile test platform for face lines and vacuum control for bed- of-nails fixtures are of course integrated production and service of in the basic configuration. A central control module handles communication electronic modules between the process controller and the modules. Analog signals coming from Thanks to its modular structure Test System TSU is a universal test platform for the DUT or internal modules via an electronic modules and systems. It can be equipped with the complete range of internal analog bus are available at analog and digital measurement devices of the well-known Rohde & Schwarz every slot. A special card allows in-circuit testers and can be expanded by means of VXI-bus instruments. Its external devices to be connected to the applications range from classic production tests to maintenance and repair. analog bus.

FIG 1 Universal Test System TSU as compact already proven their worth for some The system is equipped with modules as desktop Photo 42 319 time as employed in functional test required by the application and the assemblies at Rohde & Schwarz planned test strategy. Numerous plug-in Messgerätebau Memmingen, where the cards are available for analog and broad product line has to be adapted digital functional tests and for analog The trend towards ever decreasing size with signals ranging from DC to RF. in-circuit tests. External IEC/IEEE-bus and greater performance in electronics units or even a VXI-bus frame can addi- also makes itself felt in test technology. Hardware structure tionally be integrated. It is also possible With Universal Test System TSU Rohde to use the modules of Test Workstation & Schwarz is now entering the market The basic TSU system essentially con- Family TSA/TSAS/TSAP [1 to 3] or of for portable measuring instruments sists of a module frame with 13 slots the large TSI/TSIC/TSP systems [4] in (FIG 1). Yet there are practically no and power supply for the measure- TSU with the aid of simple interface limits set on the expandability of the ments and the DUT. Both internal and cards. Customer-specific applications system. The core elements of TSU have external expansions are possible at any are implemented on a special applica-

News from Rohde & Schwarz Number 150 (1996/I) 13 Articles

tion module. Depending on the signal duced through the use of the integrated Fixture concept requirements, different switch cards search functions. The test program can can be obtained including relay cards exchange data in both directions with A special feature of the TSU system is its for RF applications up to 4 GHz and other Microsoft-compatible products universal cost-effective fixture interface cards for high currents (max. 8 A) and that, besides the contacts for standard high voltages (max. 250/380 V). The applications, can be extended with signal can be routed via the fixture contacts for signals in the RF range up interface or in the fixture itself. TSU can to 4 GHz and for high currents and be operated as a desktop or rackmount voltages. The test system is therefore depending on the system configuration suitable for the testing of power sup- (FIG 2). plies, power electronics or RF products such as cordless phones. Further bene- System software fits are obtained through the use of a fixture system for vacuum and pneu- Like with other Rohde & Schwarz test matic drive. Removable fixture plates systems, TSU employs Software TSS contain only the DUT-specific nails, all under Windows NT for use on PCs. other recurring parts are part of the Compatibility between all systems of basic fixture. This, together with novel the test family is thus ensured. The prefabricated connecting elements, programming language is a structured means that 60 % of the costs can be high-level language with easily read- saved in comparison with conventional able commands for the measurement fixtures. functions. Various software tools and the convenient user interface enable Use in service easy and simple generation of test and maintenance programs. Analog in-circuit tests are generated automatically from the DUT’s Through its modular and flexible con- board description by the test-program figuration as well as handy size and generator. The board description can low initial outlay, TSU is ideal for use in be taken directly from the CAD system service and maintenance. Existing test via a software interface or can also programs and fixtures can be taken be manually entered. from production provided they have been tested on Rohde & Schwarz test Functional tests can again be obtained systems in the repair of modules. It is manually or simply with the interac- often possible to adopt test programs tive test generator. It is not necessary and fixtures from other test systems by to have a detailed knowledge of the using conversion programs. This results programming language since program- in high cost savings. ming itself is made by filling in forms from which the program code is gener- Especially for the military sector and ated automatically. Test steps or rou- the aerospace industry, TSU can be tines can be tried out straightaway on operated with the ATLAS test language the hardware, modified and inserted widely used in those areas. It is exactly into the test program as required. for such applications that the TSU

Measurement data can be represented FIG 2 TSU system can be integrated in 19-inch system offers an economically inter- in diagrams with the integrated trace rack for applications requiring lots of add-on units. esting alternative to the often expensive graphics and logged. and complex test systems employed up to now. Circuit diagrams and corresponding layouts can be displayed on the screen Test-data storage of the PC to avoid unnecessary time wasted on searching for circuitry or via DDE (dynamic data exchange). In order to have a continuous overview components in diagrams when debug- Thus, for example, measurement data of production quality, incoming test ging test programs or repairing DUTs. can be entered directly in Word or data have to be stored and evaluated. Search times can be drastically re- Excel forms and logged. With a view to ISO 9000 and the

14 News from Rohde & Schwarz Number 150 (1996/I) Articles

product liability law, the history of a REFERENCES product from its production to service is [1] Tschimpke, L.: Test Workstation TSA for test- [3] Hönle, H.: Power Test Station TSAP – Com- of importance. In the long run, high ing in electronics production and service. plete testing of electronics power circuits. News from Rohde & Schwarz (1991) News from Rohde & Schwarz (1994) product quality can only be guaranteed No. 132, pp 4–7 No. 145, pp 11 –13 through systematic documentation of all [2] Schröder, D.: Test Workstation TSAS tests [4] Schneider, J.; v. Gagern, C.: Performance work carried out during its life cycle. complex boards in electronics production. tests on printed circuits using TSP and CATE. Klaus Kundiger; News from Rohde & Schwarz (1992) News from Rohde & Schwarz (1989) Dr. Lothar Tschimpke No. 138, pp 4–7 No. 124, pp 4 –11

Condensed data of Universal Test System TSU Test methods analog in-circuit test, analog IC check, analog/digital functional test, emulation test, boundary scan test, LaserVision test Analog tests various signal sources and measuring instruments for integration as modules or external units, internal analog bus, instrument multiplexer for external units, signal relays for frequency range DC to 4 GHz, number of pins expandable to 576 Digital test module for static test (data rate max. 50 kHz) or dynamic test (data rate max. 10 MHz), level range up to ±30 V, number of pins expandable to 256 Computer standard PC with Windows NT operating system Software TSS Windows, interactive test generator, trace graphics, quality management, paperless repair, graphic debugging software, graphic repair station, CAD/CAE link Reader service card 150/03

Installing directional antennas for microwave WLANs Test hint

Life without PC networking is hard to imagine in conventional RF measurement devices like power Hop length Loss the offices and labs of modern enterprises as it meters or spectrum analyzers. This does not 1 km 50.3 dB opens up communication facilities for everyone. exactly make life easy for someone installing 2 km 56.3 dB Up to now most networks have been based on radio-link hops, because the antennas of the 3 km 59.8 dB coaxial cables, which are expensive to lay. transceiver stations have to be aligned spot on. 4 km 62.3 dB Thanks to drops in the prices of integrated cir- “Eyeballing” may work for short distances, but 5 km 64.3 dB cuits, wireless local area networks (WLANs) are another more “far-sighted” method has to be being seen in a more favourable light because of found for hop lengths in the km range. Path loss between transmitter and receiver at 2.45 GHz, the economic advantage. It is also obvious that antenna gain 25 dB portable computers like notebooks can be net- If the transceivers are replaced (as shown in the worked in this way, but the same also applies to FIG) by a Signal Generator SMP at one end of whole buildings and remote factory sites which the microwave link and a Power Meter NRVD could have a wireless connection with the main with sensor (or spectrum analyzer) at the other, to generate a CW signal at the ISM frequency of network. This is also a sound approach for coun- antennas are very easy to align. SMP is used 2.45 GHz and a level of +20 dBm for instance tries with an infrastructure that is still being (all SMP02s and SMP22s can do this). Assuming expanded. Short-hop microwave links on the each antenna has a gain of 25 dB and the hop 2.45 GHz ISM frequency are ideal for this pur- SMP NRVD length is 5 km, a path loss of approx. 64.3 dB pose. Spread-spectrum methods such as frequen- (TABLE) is obtained, ie the power meter displays cy hopping or the direct-sequence spread-spec- –44.3 dB for optimally aligned antennas. trum method make it possible to operate several Wilhelm Kraemer adjacent networks on the same frequency without mutual interference or any risk of eavesdropping. Sensor (eg NRV-Z4) When such an approach is used, energy is transmitted over a large frequency band (approx. 2 MHz) and the signal cannot be detected with Reader service card 150/04 for further information on SMP

News from Rohde & Schwarz Number 150 (1996/I) 15 Articles

TV Monitoring and Test Systems TS6100 also be configured as monitoring systems (dual solutions). The operator can use these basic systems together Video and audio parameters of with the available options to create an optimal solution to fit the monitoring TV transmitters all under control and measurement tasks required.

High availability is an extremely important factor in the operation of broadcast Monitoring System TS6110 uses a transmitters. This is why many network operators increasingly make use of video PC card for video measurements. automatic monitoring systems enabling them to estimate failure probability at This card can be installed in any IBM- an early stage. System family TS6100 from Rohde & Schwarz offers individual compatible computer as the system soft- solutions for on-air and off-air monitoring and testing of TV transmitters and ware runs under Windows 3.1. Since CATV systems. transmitters are known to generate high field strengths, it is advisable to use a well-shielded (against EMI) PC – eg Broadcasters are under an obligation • a variety of configurations ranging PSM7 from Rohde & Schwarz [1]. to ensure the transmission and distri- from minimal to all-in solutions, TS6110 is a low-cost monitoring system. bution of programs with guaranteed • upgradability, reliability – usually 99.9%, ie no more • remote control and remote polling, Video Measurement System VSA [2] than nine hours outage per year. The • statistical evaluation of test data. is the core component of Monitoring TV monitoring and test systems of the System TS6120. In its minimum con- TS6100 family from Rohde & Schwarz System family and uses figuration the 486/66 processor in the (FIG 1) provide the network operator VSA also serves as a system controller. with an economical solution to meet Within the TS6100 system family, a ba- For more complex applications an ex- this requirement. Key features of the sic distinction is made between monitor- ternal controller can be used. Numer- system are: ing and measurements. TS6110 and ous options allow adaptation to spe- • modularity, TS6120 are designed for monitoring cific tasks (FIG 2). In this context the • use of standard components (hard- purposes, whereas TS6130, TS6140 AMON audio option should be partic- ware and software), and TS6150 are test systems which can ularly mentioned; it enables the user to monitor audio parameters on the air without interrupting the program, as the audio signal itself is used as a test signal. At the same time additional data (eg dynamic RDS data) can be transmitted on the audio line; thus costly data lines are not necessary.

Test System TS6130 was specially designed for on-air measurements during program time. The introduction of solid-state technology has led to a change in the design concept of transmitters. Today single transmitters (sometimes with a passive exciter standby) are used rather than dual transmitters. This means that it is no longer possible to carry out measurements and change settings on standby transmitters, but FIG 1 only on operating transmitters. The TV Test System TS6130 with Video basic version of TS6130 consists of Measurement Video Measurement System VSA, multi- System VSA, CCVS standard CCVS Generator SFF [3] and Generator SFF and System Software TS6100/Win. SFF Audio Monitoring System AMON produces a standardized CCVS video Photo 42 233 signal and allows the generation of

16 News from Rohde & Schwarz Number 150 (1996/I) Articles

TV transmitters 1-n Video 1-n

Audio 1-n

Audio Monitoring System AMON Monitor

Audio

Video 1-10 Audio/video Audio 2 x 1-10 switch

Video Printer Audio

Video Video 1- 4 Modem Measurement RS-232-C RS-232-C RF System VSA Computer IEC/IEEE bus FIG 2 RS-232-C Block diagram of GPS receiver

TV transmitter GPS antenna with Monitoring RF 1- 6 RF combiner Keyboard Mouse System TS6120 (blue: options)

individual test signals. The most impor- system is used for testing the transmitter Software TS6100/Win can perform all tant parameters of baseband, teletext, outside program times. The system also monitoring and testing tasks using RF signal (eg vision-carrier phase) and incorporates a precision demodulator, five different modes: audio signal are measured and a process controller, a switching panel evaluated. This enables transmitter and the system software. Traditionally, • The automatic mode is primarily alignment to be performed during tests on TV transmitters are carried out used to monitor and observe se- program emission. by means of a network analyzer. It can lected parameters. This is performed be used to measure amplitude and at fixed times of the day and can be Full-Field Test System TS6140 is based group-delay frequency response at the continued over several days, weeks, on Spectrum Analyzer FSEA20 [4]. video frequency as well as at the IF/RF. months or even years. If one of the Group delay is measured by a com- Using TV Network Analyzer SOKF, parameters exceeds or falls below a bination of CCVS Generator SFF and the built-in oscilloscope also serves to set limit value, an alarm is triggered Video Analyzer VSA. Further system evaluate video signals in the time which, in case of an attended station, components are a precision demodu- domain. Similar to TS6140, TS6150 is displayed on the screen or other- lator, a process controller, a switching can carry out checks on the transmitter wise transmitted via modem to a panel (for RF, IF and AF) and System for compliance with standard specifi- Software TS6100/Win. The controller cations. and the switching panel form the core of the system. All signals, from RF Software TS6100/Win through IF to AF, are directed to the appropriate inputs and outputs of the TV Monitoring and Test Systems TS6100 instruments depending on the type of use System Software TS6100/Win measurement carried out, so there is no (FIG 3) for monitoring and measure- need for tedious manual switching. This ments. Statistical evaluation of the data system can be used to check the com- obtained is carried out by the supplied pliance of transmitters with standard macros, using either MS-Excel or specifications. MS-Access. Advantages of Windows 3.1 as a graphic user interface are stan- TV Network Analyzer SOKF/SWKF [5] dardized operation, multitasking and is the heart of Full-Field Test System versatility with regard to integration FIG 3 System Software TS6100/Win to run TS6150. Similar to TS6140, the TS6150 into other programs. under Windows 3.1

News from Rohde & Schwarz Number 150 (1996/I) 17 Articles

control center. Of course, all data unit. The automatic tests defined by REFERENCES are stored locally and can be re- scripts are started in this menu. The [1] Bues, D.; Stegmaier, J.; Vahldiek, D.: Indus- trieved for evaluation at any time. automatic and the interactive test trial Controller PSM – Automated testing and control in production and lab. News • The interactive mode is used for modes are also started here. from Rohde & Schwarz (1994) No. 146, quickly checking subranges. The pp 19– 21 automatic mode is in the meantime The Options menu is used for defini- [2] Bichlmaier, T.; Finkenzeller, R.: Video Meas- set on standby. tion of the unit configuration with the urement System VSA – Four TV measuring • The direct mode serves to select interface (eg IEC/IEEE bus, RS-232-C, instruments plus controller in one compact unit. News from Rohde & Schwarz (1995) individual units via virtual user inter- TTL, AT bus) and the path configura- No. 147, pp 18–21 faces for fast settings and tests. tion. Communication configurations [3] Mahnken, D.: SAF and SFF, the new video • Run script is provided to trigger a can also be selected in this menu. generators for TV measurements. News particular measurement (script). The With remote-controlled transmitters it from Rohde & Schwarz (1992) No. 138, scripts – a macro language – enable is essential that alarm, fault and pp 14 –17 the user to create his own tests. query messages are not displayed on [4] Wolf, J.: Spectrum Analyzer FSEA/FSEB –- New dimensions in spectral analysis. News Debug aids and test facilities are the screen but transmitted to a con- from Rohde & Schwarz (1995) No. 148, contained in the script development trol center, eg via a modem, where the pp 4 – 8 environment and facilitate the crea- necessary corrections can be taken. [5] Dürselen, A.; Ebersberger, G.; Osterloh, G.: tion and modification of scripts. Optionally the messages can be stored TV Network Analyzer SWKF – State-of- • Run sequence serves for the compi- in a log file. Access levels and pass- the-art TV sweep measurements from 0.01 to 900 MHz. News from Rohde & Schwarz lation of individual measurements in words are also assigned to the individ- (1994) No. 144, pp 26 –28 any combination. In this way individual users. ual tests can be grouped together and retrieved as necessary. System-related services

Test results are documented by a printer The presales and aftersales services in the form of graphs or tables. The re- provided by the supplier are an essen- port can be configured according to tial prerequisite for the customer to be the user’s wishes. With dynamic data able to use a system efficiently. A com- exchange (DDE) data can be sent petent advisory service guarantees that between different Windows programs. system design is optimally matched to The option concept makes the software the customer’s particular requirements. easy to use and upgradable. Drivers Comprehensive functional tests, proper needed for external equipment and commissioning and practice-oriented additional software options are added training make for fast availability of to the software kernel. Due to its mod- the system without undue delay. In ad- ular design, the software is extremely dition to these standard services, Rohde flexible. Passwords and a number of & Schwarz offers longterm support in access levels safeguard security in the terms of customized maintenance pro- use of the software package. They grams. guarantee that test data are processed Michael Lehmann; Gerhard Strauss by licenced users only and that system configurations are exclusively performed by authorized personnel.

Graphic user interface

In addition to the usual Windows Condensed data of TV Monitoring and Test Systems TS6100 menus File, Edit, Window and Help, Frequency range TS6100/Win software includes two TS6110 / 6120 / 6130 / 6150 45 to 860/900 MHz TS6140 9 kHz to 3.5 GHz further menus – Measurement and Test modes automatic, interactive, direct, Options. run script, run sequence Software TS6100/Win (under Windows 3.1) The Measurement menu serves to Interfaces IEC/IEEE bus, RS-232-C, TTL, AT bus operate individual units interactively. Reader service card 150/05 A virtual interface is provided for each

18 News from Rohde & Schwarz Number 150 (1996/I) Articles

Spectrum Analyzer FSE with Option FSE-B7 Spectrum Analyzer FSE [1] with Vector Signal Analyzer Option FSE-B7 is the first instrument to fulfil all the requirements specified in the various stan- Vector signal analysis – indispens- dards for measuring the RF parameters of digitally modulated signals. In other able in digital mobile radio words, it meets the stringent requirements made on measurements in the Spectrum Analyzer FSE not only performs measurements in the spectral domain spectral domain with respect to dy- with high precision and wide dynamic range. Now, with its new vector signal namic range, intermodulation charac- analyzer option, it can also demodulate all signals used in mobile radio, both for teristics and phase noise. At the same analog and digital modulation, and measure their modulation parameters. time it supplies the time reference for burst measurements and measures modulation parameters and errors with high accuracy (FIG 1).

These unique capabilities of FSE were achieved by combining a high-grade spectrum analyzer with a vector signal analyzer. After the common RF frontend up to 3.5 GHz or 7 GHz and the IF selection, the IF signal is divided into one path for the scalar spectrum analyzer and another for the vector signal analyzer (FIG 2). In the spectrum analyzer the IF signal is logarithmized and recti- fied. At the output, the magnitude of the FIG 1 Spectrum Analyzer FSE with vector signal an external trigger for this measure- test signal is available; the phase infor- analyzer option for measuring digital modulation ment, ie the signal must be supplied by mation is lost in the process. The advan- parameters the DUT. Therefore only DUTs capable tage of this method is the wide dynam- of supplying such a signal can be used, ic range attainable with logarithmic lev- With digital modulation methods, not and only qualitative measurements are el display as a result of level compres- only the spectrum of the transmitted possible. Scalar spectrum analyzers sion performed by a log amplifier. In signal is of interest but also its behav- are completely unsuitable for determin- the stages following the log amplifier, iour in the time domain and the quality ing the modulation error of the RF sig- only the compressed signal is proof the complex modulation. Conven- nal. These errors are however specified cessed. Here FSE attains a dynamic tional scalar spectrum analyzers pro- for all digital radio transmission stan- range of 110 dB. In the vector signal vide measurements in line with standards and must therefore be measured. analyzer the IF signal is sampled directly dards only for the RF parameters, eg in- channel power, occupied bandwidth, adjacent-channel power or spuria of digitally modulated signals in the fre- FIG 2 Vector signal analyzer quency domain. However, for measur- Block diagram In-phase signal ing power as a function of time, which of FSE with vector is required for TDMA transmission signal analyzer methods for example, reference must De- Signal modu- usually be made to fixed synchroni- memory lation zation sequences such as pre- or mid- ambles. Since the time reference is in- Result RF frontend IF calculation cluded in the information carried by the IF selection and display signal, the RF signal must be demod- Quadrature signal ulated down to bit level. The bits are Log. Peak/ used as a trigger reference for repre- detector sample detector senting and measuring the burst. Con- Video filter ventional spectrum analyzers require Scalar spectrum analyzer

News from Rohde & Schwarz Number 150 (1996/I) 19 Articles

by an A/D converter and digitally and evaluates it in accordance with the below and displays the results on the mixed into the baseband. In this pro- modulation type entered. monitor: cess the real and the imaginary compo- • magnitude and phase, or frequency, nent of the test signal, or its magnitude Thus all RF signals commonly used and as a function of time, and phase respectively, are obtained. standardized in mobile radio can be • in-phase and quadrature signals, Thus the complete signal information processed: • eye and trellis diagrams, is available for analysis. Basically the • GSM, DCS1800 (PCN) or DCS1900 • vector representation in polar dia- vector signal analyzer could also be (PCS) worldwide, gram, used as a spectrum analyzer. However • NADC (North American digital • constellation diagram, the A/D converter would reduce the cellular), • table with demodulated bits. dynamic range of the scalar spectrum • Qualcomm CDMA (code division analyzer. For this reason, FSE with its multiple access), FIG 3 shows a vector representation vector signal analyzer option offers • PHP (personal handy phone, Japan), of a TETRA signal in a polar diagram. both methods and uses them optimally • PDC (personal digital cellular, Japan), TETRA uses π/4-DQPSK modulation at as required for the measurement in • DECT (digital European cordless a data rate of 36 kbit/s. question. telephone, Europe, Canada), A variety of trigger functions is available for selecting a specific part of the signal. Coarse triggering can be performed free-running, level-dependent or by means of an external signal. The trigger determines the start of reading the measured values into memory. A particular burst can be searched for in the memory. This is especially impor- FIG 3 Vector diagram of tant for TDMA signals, which transmit TETRA signal information in time slots. It is also possible to synchronize on bit sequences of the signal. Signal display will in Demodulation of signals with • CDPD (cellular digital packed data), this case be related to synchronization analog and digital modulation • MOBITEX (mobile data system), sequences in the signal (eg midamble • TETRA (Trans-European trunked in GSM bursts). With the vector signal analyzer option, radio), FSE can handle all types of modula- • ERMES (European radio message Measurement of tion commonly used in mobile radio, system), modulation errors whether analog methods such as AM • CT2/CT3 (cordless telephone), or FM or digital modulation such as • APCO25 (Association of Public Among the most important measure- 2FSK, 4FSK, BPSK, QPSK, DQPSK, Safety Communications Officers, ments on digitally modulated signals is offset QPSK, π/4-DQPSK, 8PSK, Project 25), the determination of modulation errors. 16QAM, MSK and GMSK. Ideal signal • TFTS (terrestrial flight telephone Depending on the type of modulation sources for such tests are the Rohde & system). used, the phase error (modulation Schwarz Signal Generators SME and with constant amplitude, eg GSM) SMHU58 [2]. In the case of digitally These standards can be directly called or the phase and amplitude errors modulated signals, all that has to be by means of softkeys. FSE evaluates (modulation with amplitude and phase done is to enter into FSE the modulation signals according to the criteria listed component, eg NADC, TETRA, PHP, type, symbol rate and receive filter. With this information, FSE demodulates the RF signal down to bit level. The symbol rate is freely selectable up to Frequency and Amplitude/ Test signal clock phase Receive Test signal 1.6 Msymbols per second. As receive synchronization correction filter (I/Q) filters, Gaussian, cosine and root cosine filters with user-selectable parame- Reference- FIG 4 Symbol Reference Reference signal ters are available. The demodulator of detector filter signal (I/Q) Processing steps in generator FSE-B7 is synchronized to the frequency FSE for determining Bits for symbol and the symbol clock of the test signal modulation errors table

20 News from Rohde & Schwarz Number 150 (1996/I) Articles

user interface and remote control. Otherwise the PC is free for application programs run on FSE. Measurement speed is not reduced as there is no time- sharing with test runs. Measurements FIG 5 as well as the evaluation and display Phase error of GSM burst shown over of results are handled by a network of useful burst range five transputers. The demodulators and modulation measurements are implemented by means of four digital signal PDC) are of interest and specified in transmission channel. Timing is defined processors coupled to the transputer the relevant standards. For error cal- in the form of tolerance masks, which network. For GSM phase-error calcula- culation FSE generates the analog, each transmitter must comply with. A tion for example, the high computing ideally modulated signal in the base- synchronization sequence in the signal power enables up to five measurements band (I/Q level) from the demodulated (eg the midamble with GSM, DCS1800 per second. bit stream. FIG 4 shows the processing or DCS1900) is mostly used as a steps. time reference for the tolerance masks. With its excellent characteristics in Accurate measurement of the burst spectral and vector signal analysis For calculation of modulation errors, all characteristic is therefore possible only and its high flexibility, FSE is an ideal parameters of the measured signal and by demodulating the signal. Using the development tool. For applications in the reference signal are compared. The vector signal analyzer, FSE exactly production, the high measurement result can be represented as a trace determines the time reference by evalu- speed and configurations in line with versus time or symbols, or output numer- ating the demodulated bits and allocat- standards make FSE a value-for-money ically as a sum value in an error table. ing them to the stored samples. With one-box solution for all measurements FIG 5 shows the phase error of a GSM eight samples per symbol, the error lim- of RF parameters on transmitters. burst versus time as an example of a its for the time reference are <6.25% Josef Wolf modulation-error measurement. of symbol period without clock synchronization, and <1% of symbol The error limits of the instrument itself period with clock synchronization. play an important role in modulation- error measurement. In practice the in- Measurement speed strument should have an accuracy ten times better than that of the DUT. In the FSE not only sets new standards in REFERENCES case of GSM for example, a maximum spectral analysis in terms of dynamic [1] Wolf, J.: Spectrum Analyzer FSEA/FSEB – rms phase error of 5° and peak phase range, precision and measurement New dimensions in spectral analysis. News error of 20° are allowed. FSE offers speed, but also in modulation analysis. from Rohde & Schwarz (1995) No. 148, pp 4–8 excellent values especially with regard The high measurement speed is based [2] Lüttich, F.: New signal-generator characteris- to phase noise, so that for GSM phase on computing power not common in tics to satisfy needs of digital mobile radio. measurements a residual error of <0.5° spectrum analyzers so far. An internal News from Rohde & Schwarz (1995) (typ. 0.2°) rms and <1.5° peak can be 486 PC is provided for handling the No. 149, pp 44 –45 guaranteed. For π/4-DQPSK modulation used by NADC, TETRA or PDC, the error vector magnitude is <0.7% rms and <2% peak. The tolerances per- Condensed data of vector signal analyzer of FSE mitted by the standards can thus be Frequency range 100 kHz to 3.5/7 GHz practically completely allowed for the Demodulators AM/FM/PM, 2FSK, 4FSK, BPSK, QPSK, DQPSK, π DUT as no significant part is taken up O-QPSK, /4-DQPSK, 8PSK, 16QAM, MSK, GMSK Symbol rate max. 1.6 Msymb/s by the measuring instrument. Receive filters Gaussian, cosine, root cosine, α/BT = 0.2 to 1 Display modes magnitude, phase, frequency, eye/trellis diagram, Power measurements vector diagram, constellation diagram, in time domain demodulated bits Measurements magnitude error, phase error, frequency error, error vector (magnitude), I/Q offset, I/Q imbalance In the case of transmission methods using time multiplexing, each subscriber Reader service card 150/06 is assigned a specific time slot in the

News from Rohde & Schwarz Number 150 (1996/I) 21 Articles

Digital Monitoring Direction Finders DDF0xM Besides the classic DF method based on the Watson-Watt principle, these direction finders offer state-of-the-art corre- State-of-the-art monitoring lation methods, which afford many advantages over classic methods: direction finding from HF to UHF • extremely high accuracy, sensitivity and flexibility, The compact, remote-controllable Digital Monitoring Direction Finders DDF0xM • use of wide-aperture, circular-array are of modular design and operate as correlative interferometers or on the antennas with a minimum number of proven Watson-Watt principle. They can easily be integrated into computer- radiators (eg circular arrays 1 m in controlled receiving systems, eg for postal radiomonitoring, in the military sector, diameter with nine antenna elements for police, border guards, customs and coastguard authorities. A wide range of covering the wide frequency range antennas is available for stationary and mobile uses, including wide-aperture 20 to 1300 MHz, or a single array systems, which afford high accuracy and sensitivity even under harsh environ- approx. 50 m in diameter for the mental conditions. complete shortwave range),

FIG 1 User interface of digital HF-VHF-UHF the frequency range 0.3 to 3000 MHz • high flexibility with respect to antenna Monitoring Direction Finder DDF0xM in fixed- (FIG 1). DDF0xM direction finders can geometry, frequency mode and VHF-UHF DF antenna also be used for scanning, the prob- • in mobile use, very effective reduc- ability of intercept being markedly tion of DF errors introduced by plat- The Rohde & Schwarz doppler Direc- higher than that of conventional direc- form possible through calibration, tion Finders PA010 and PA055 and their tion finders, which can process the sig- • use of correlation coefficient as cri- mobile counterparts PA510 and PA555 nal in only one channel at a time. The terion for DF quality, have for many years been a great suc- direction finders of the DDF family ana- • use as a first step towards high- cess all over the world. It is in the nature lyze all signals within a frequency win- resolution DF methods. of the doppler principle that the capa- dow simultaneously with the selected bilities of these direction finders are lim- resolution. In the search and scan To measure the complex antenna ited when it comes to intercepting very modes the direction finders behave like voltages, DF receivers of one through n short signals as used in frequency hop- several DF units connected in parallel. paths can be employed. DDF0xM uses ping, burst and GSM transmissions. For a three-path vector voltmeter which uncomplicated bearings on such signals, The DDF direction finders first deter- is capable of monopulse processing Rohde & Schwarz has developed a new mine the complex voltages of the DF (eg using the Watson-Watt method). generation of direction finders using antenna and from these calculate the The voltmeter is based on VHF-UHF digital signal processing: DDF0xS for azimuth and, if desired, the elevation. Receiver ESMC [2], which turns the fast scanning [1] and the brand-new The DF method used can be selected DF unit into a high-quality DF receiv- DDF0xM mainly for monitoring tasks in as required to match the task on hand. er. Wide-aperture DF antennas are

22 News from Rohde & Schwarz Number 150 (1996/I) Articles

Range of antennas Tuner

HF Two types Tuner Control of DF antenna are available DF antenna for DDF direction finders (FIG 3): Tuner Synthesizer HF • compact Antennas ADD115 and A/D Digital ADD155 capable of handling mono- converter signal Transputer processing VHF/UHF pulses and designed for maximum Tuner DF speed, which together cover the VHF-UHF Control RS-232-C Tuner Control range 1 to 650 MHz (Watson-Watt DF antenna method), Tuner Synthesizer PC card • correlation DF Antennas ADD011,

GPS GSM ADD050, ADD150, ADD051 and synchronization ADD070 characterized above all Tuner by high DF accuracy and immunity UHF Tuner Control DF antenna to multipath propagation.

Tuner FIG 2 Components of Digital Monitoring Direc- tion Finder DDF0xM The following features are common to all seven antennas: • large bandwidth, scanned in pairs, resulting in short DF time bandwidth of 200 kHz (VHF/UHF) • integrated lightning protection times even for this type of application. or 25 kHz (HF) using fast Fourier trans- (ADD150, ADD050 and ADD051 form and polyphase filter banks. protected as standard against Design and operation direct strokes), In their basic version, DDF0xM direc- • wide dynamic range, The monitoring direction finders are tion finders have no display or control • compact design, available in the following versions: elements on the front panel apart from • connector for electronic compass. • DDF01M for HF (0.3 to 30 MHz), status-signalling LEDs. The direction • DDF05M for VHF/UHF (20 to finders are operated via an external PC 1300/3000 MHz), running under the MS Windows NT™ • DDF06M for HF/VHF/UHF (0.3 to operating system; the DDF operating 1300/3000 MHz). software is supplied as standard. The digital processing unit is optionally In the three-path receiver frontends the available with a built-in PC and a received signal is converted to an IF of colour TFT display (approx. 12 cm x 768 kHz (FIG 2). In the digital process- 16 cm; 480 x 640 pixels). For this ing unit the IF is digitized with 16-bit version, special emphasis was placed resolution and processed with a real- on the effective suppression of computer-specific EMI, which is of particular importance for direction finders installed in vehicles, as in this case the DF antenna and the DF equipment are FIG 4 HF DF Antenna ADD011 (0.3 to 30 MHz, FIG 3 Overview of DF Antennas ADD (blue for usually located close to each other. correlation method) Photo 42 342 mobile, yellow for stationary use)

HF antennas: The compact ADD115 for the frequency range 1 to 30 MHz, which is only 1.1 m in diameter and accommodated in a radome, is made up of two orthogonally arranged loops and an omnidirectional antenna. Its compact size and lightweight but sturdy construction make this antenna ideal for mobile use. Antenna ADD011 for 0.3 to 30 MHz (FIG 4) is intended for stationary and transportable use

News from Rohde & Schwarz Number 150 (1996/I) 23 Articles

UHF antenna: Antenna ADD070 is available for the frequency range 1300 to 3000 MHz. It is designed as a circular-array antenna with a central reflector and can be mounted on a single mast together with the VHF-UHF antennas.

Operating modes

The most important operating mode of DDF0xM direction finders is the fixed- FIG 5 frequency mode (FFM). In FFM (FIG 6), VHF-UHF DF the direction finder can be matched Antenna ADD051 to the signal characteristic in various (20 to 1300 MHz, correlation method) ways. As to the display type, a histo- Photo 42 334/1 gram can be selected besides conventional (three-digit) numeric and polar representation with display of the and allows direction finding even of strokes as standard and can thus with- elevation angle and DF quality indica- skywaves of high angles of elevation out any restrictions be mounted on tion. In addition the spectrum about as well as determination of elevation masts and buildings. Antenna ADD050 the receive frequency (±12.5 kHz in angle, thus enabling fixing of signal offers enhanced accuracy and sensi- the HF range, ±100 kHz in the VHF- sources using the single-station-location tivity in the frequency range 20 to UHF range) can be shown in realtime (SSL) principle. 200 MHz. This circular-array antenna with selectable resolution.

FIG 6 User interface of DDF0xM in fixed-frequency mode FIG 7 User interface in scan mode

VHF-UHF antennas: Antenna ADD150 with a diameter of 3 m is suitable for With its short DF times (minimum signal is designed for universal applications in stationary and transportable applica- duration ≤ 500 µs for VHF-UHF, as the frequency range 20 to 1300 MHz. tions. DF Antenna ADD051 (FIG 5) short as 10 µs with monopulse ampli- It is accommodated in a radome 1.1 m is a combination of ADD050 and tude processing) and with external in diameter and about 0.2 m high. This ADD150 mounted on a common mast. synchronization, DDF05M can take compact size makes the antenna an It covers the complete range of 20 to bearings even of GSM signals. Since, ideal choice for applications onboard 1300 MHz with maximum accuracy with the correlation method, not only vehicles, ships and aircraft. The anten- and sensitivity. the azimuth but also the elevation of na is protected against direct lightning skywaves is determined in the HF

24 News from Rohde & Schwarz Number 150 (1996/I) Articles

range, DDF01M is equally suitable mission rate of the data link used. The REFERENCES for single-station location (software WinLoc radiolocation program [3] pro- [1] Bott, R.: Digital Direction Finder DDF – option). vides a driver that allows integration of Modern scanning direction finding from 0.5 to 1300 MHz. News from Rohde & Schwarz DDF0xM direction finders operating in (1994) No. 146, pp 26–28 Apart from the fixed-frequency mode, fixed-frequency mode into triangulation [2] Boguslawski, R.; Egert, H.-J.: VHF-UHF Com- DDF0xM direction finders can be oper- systems. pact Receiver ESMC – Easy radio detection ated in the search and scan modes, Franz Demmel; Ulrich Unselt; in VHF-UHF range. News from Rohde & where the advantages of the large real- Dr. Eckhard Schmengler Schwarz (1994) No. 143, pp 11–13 time bandwidth used for spectral anal- [3] Alberter, G.; Deutges, H.; Hinkers, G.: Radio- location with standard software WinLoc. ysis come into their own. In the scan News from Rohde & Schwarz (1994) mode (FIG 7) the direction finders No. 144, pp 42–43 scan a range defined by a start and a stop frequency and with selectable Condensed data of Digital Monitoring Direction Finders DDF0xM resolution. Only those bearings that are above a preset threshold are indi- DDF06M DDF01M DDF05M cated, and scanning is not interrupted Frequency range 0.3 to 30 MHz 20 to 1300 (3000) MHz upon detection of a signal. In the DF method correlative interferometer, Watson-Watt search mode, on the other hand, oper- DF error <1° RMS with ADD011 <1° RMS with ADD051 ation is interrupted for a selectable Sensitivity typ. 1 µV/m with ADD011 typ. 1 µV/m with ADD051 dwell time when a signal above Operating modes FFM, scan, search threshold is detected so that the signal Realtime bandwidth 25 kHz 200 kHz can be examined in more detail. Dynamic range 120 dB Searching and scanning cannot only Minimum signal duration <5 ms <500 µs be performed over specified frequency Demodulation AM, FM, SSB ranges but also in individual, stored Displays channels (up to 1000). FFM numeric and polar DF value, DF quality, level, elevation, spectrum within realtime bandwidth, DF value versus time (waterfall diagram) DDF0xM direction finders can of Scan levels and DF values versus frequency, frequency versus course be remote-controlled in all time (waterfall diagram) functions and over any distance. Func- Reader service card 150/07 tionality depends however on the trans-

Matsushita relays in Audio Analyzer UPD measure the best of audio Reference

“When the sounds of hifi units or amplifiers are a compact, general-purpose instrument for de- measured, relays are often to be found. Like termining all audio parameters on analog and in Audio Analyzer UPD from Rohde & Schwarz, digital interfaces. The excellent quality of this instrument with its integrated PC owes much to its digital technology.” This praise of our Audio Analyzer UPD appeared in an application report in “newsline” (May 1995) from Matsushita Auto- mation Controls Deutschland GmbH.

Matsushita Automation Controls is a group that operates worldwide. It markets precision components and systems for plant automation, and is an affiliate of Matsushita Electric Works Ltd, Japan, one of the world’s biggest electric concerns. The production range includes relays, sensors, stored-program controllers and image- timers and counters, switches and connectors, processing systems. Sö

News from Rohde & Schwarz Number 150 (1996/I) 25 Articles

Solid-state UHF TV Transmitter NH500 • patented R&S circuits for power control, phase regulation and characteristic correction, The new reference for • exciter with precorrection of nonlinear output-stage characteristics, TV transmitters: ecoTV regulated output power for vision and sound, regulated modulation About a year after the presentation of its solid-state TV transmitter for band III, signals, synthesizer, precision offset, Rohde & Schwarz is launching the solid-state TV Transmitter Family NH500 SAW vestigial-sideband filter, sync- for band IV/V. Thanks to its modularity, transmitters with output power from 5 to pulse regeneration, dual-sound cod- 30 kW can easily be implemented at a favourable price. Any standby concepts ing and memory with four transmitter as well as different standards are possible. basic setups including precorrection,

FIG 1 Solid-state UHF TV Transmitter NH500, (many identical plug-in modules), even • split vision/sound amplification, the TV transmitter nicknamed ecoTV for operation with only a single trans- • broadband amplifiers and power mitter. couplers from 470 to 860 MHz, • bipolar high-power double transis- The new solid-state UHF TV transmitters The transmitter is nicknamed “ecoTV” tors, of the NH500 series (FIG 1) presented as it consumes little power, requires little • low junction temperature of output- by Rohde & Schwarz at the TV Sympo- space and is low on logistics due to stage transistors (<120°C/APL = sium 95 in Montreux [1] operate, like identical vision and sound amplifiers. 50%), solid-state VHF Transmitters NM..5 [2], This means savings in operating costs • power supply with primary-switched with Exciter SD200. This exciter with and also in infrastructure. Solid-state regulators for very high efficiency, all-electronic tuning is designed for PAL, Transmitters NH500 have the following • microprocessor-based transmitter PALplus, NTSC or SECAM colour-tele- main features: control unit for operation, monitor- vision transmission as well as for dual- • clearly arranged, modular configu- ing and remote control, sound and stereo operation (IRT or ration, • integrated automatic switchover for NICAM). It directly drives the amplifier • power stages 5/ 7.5/10/15/20/ option “passive exciter standby”, modules for vision and sound (FIG 2) 30 kW, “active dual output stage”, “passive without the use of preamplifiers. Very • no signal degradation on removal of transmitter standby“, high transmission reliability is guaran- power amplifiers, • very low heat dissipation thanks to teed by the multiple redundancy of all • protection facility in each amplifier forced-air cooling, RF power stages and power supplies and power supply, • high transmitter efficiency,

26 News from Rohde & Schwarz Number 150 (1996/I) Articles

• optional PAL, PALplus, NTSC or the vision carrier prevents spurious for dual-sound operation to IRT and SECAM transmission, emission in the lower vestigial side- NICAM. Setting of the exciter is fully • optional parallel or serial remote band. A built-in lightning arrester pro- electronic by software. All parameters interface. tects the transmitter output from light- such as basic setting of levelling or out- ning strokes at the antenna. put-stage-specific precorrections are set Mechanical design from the display unit using the keypad and operation The micropocessor-based transmitter and rollkey and are stored in non- control unit handles the switch-on volatile memory. For special conditions, The interfaced modular design through- sequence, monitoring, display, LED in- such as operation at reduced power, out allows virtually all possible trans- dicators and remote control. The hard- for repairs or (n+1) standby, four mitter configurations with regard to ware for controlling “passive exciter configurations can be defined for level, location and customer standby con- standby”, “active dual output stage” or linearity and group delay for example. cepts. The transmitter is divided into “passive transmitter standby” is already The exciter can be set to a new con- two racks. The exciter rack accom- integrated. To activate any of these, the figuration by command. modates Exciter SD200, a transmitter RF switches with control and RF cables control unit with display panel and and software are all that is required. The vision and sound amplifiers are of remote interface, vision/sound diplexer identical design. The amplifier plug-in is and colour-subcarrier trap. The power- Exciter and rated for 1.5 kW sync peak power and amplifier rack houses vision and sound 1.5-kW broadband amplifier for 900 W CW or peak sound power amplifiers including power couplers, (dual-sound operation). It comprises a absorbers, power supply and har- Exciter SD200 is used to produce regulated predriver with integral input- monics filter. This rack can have up to standard RF vision and sound signals, power monitor, level and phase control ten plug-ins to provide vision power of to regenerate sync pulses and to ac- as well as a class-A driver stage for 10 kW and sound power of 1.8 kW. commodate precorrectors for linear, the drivers of class-AB output-stage tran- For higher power, further racks with nonlinear and dynamic errors in the sistors. Eight output-stage modules de- amplifier plug-ins are simply added to output stage. It is equipped for split or coupled from each other and for power the transmitter. A monitoring unit inte- combined amplification and designed of 220 W each are combined to obtain grated in each rack signals operating nominal power of 1.5 kW (vision) or states to the central control unit. 900 W (sound). The total gain of the plug-in is approx. 53 dB. The power The amplifier and power-supply plug- coupler with integral directional cou- ins are self-engaging (supply voltage, plers for monitoring is a printed circuit RF input, RF output, control and moni- requiring no adjustment. The RF ampli- toring bus) and can be replaced with- fiers operate with standard transistors. out having to interrupt operation. After At present, transistors from four well- releasing a safety catch on the power known manufacturers are available supply, the supply voltage and thus the FIG 2 Block diagram of 10-kW TV Transmitter and can be used without having to RF power of the amplifier plug-in to be NH510 modify layout or adjustment. removed are blocked – the plug-in can be withdrawn with power switched off. The amplifier and power-supply plug- ins form an air duct. Thus, the amplifier rack merely requires an energy-saving, low-pressure cooling system. Divider

Exciter Combiner The RF power of the vision-amplifier Vision SD 200 - Vision 10 kW Sound 1 Harmonics and sound-amplifier plug-ins in the filter Colour Divider 4,43 MHz Diplexer

- Sound 1 kW Combiner rack is combined by 0° couplers in Sound 2 subcarrier trap triplate technology. The associated absorbers mounted on a heatsink are Divider Combiner Lightning placed direct in the cooling air stream. protection A diplexer feeds the vision and sound power to the common antenna line.

A colour-subcarrier trap for signals with Divider Combiner a –4.43 and –8.84 MHz spacing from

News from Rohde & Schwarz Number 150 (1996/I) 27 Articles

The amplifier plug-ins are designed air are set using the keypad and rollkey Digital signal transmission to withstand severe conditions such as and are stored nonvolatile. Up to 40 mismatch at VSWR of 1.5, a perma- transmitter defects with date and time The transmitter is ready prepared for nent all-black picture and inlet air can be stored in a large memory and future digital TV-signal transmission. temperature of +45°C. A monitor using displayed when required. All relevant Only the vision modulator and monitor the latest SMD technology protects the messages and commands according of the exciter have to be exchanged amplifier against overloading and to standard specifications are available for appropriately modified modules. signals the plug-in operational status to at the remote interface optionally in The precorrector for the class-AB output the transmitter control unit. Should a parallel (1864-1 relaying) or serial stages can handle COFDM signals 220-W power module fail, the patented (bitbus/IEC 864-2) form. (coded orthogonal frequency division power-regulating circuit prevents the multiplex). The power and level moni- other 220-W power modules from Power supply and tors in the amplifier are also ready for being driven to the full. All modules re- transmitter cooling upgrading. main at the same power level and oper- Hans Seeberger ating point without any change in dis- Two amplifier plug-ins are fed from a tortion. The same quality data are thus power-supply plug-in. To ensure high maintained. LEDs on the plug-in front reliability, the power section of the plug- panel indicate amplifier failures, VSWR in contains three identical, separate, >1.5, amplifier overtemperature and primary-switched regulators for the col- out-of-range of the RF level at the ampli- lector supply as well as two DC-voltage REFERENCES fier input. Furthermore, the RF output converters for base-current supply of the [1] Nies, J.: World première of solid-state UHF level, the RF phase and the RF threshold RF transistors. Due to the high switching TV Transmitter NH500 at TV Symposium in of the output power can be set. frequency of approx. 100 kHz, size Montreux. News from Rohde & Schwarz and weight are reduced to a minimum (1995) No. 149, p 46 Transmitter control unit, and power-supply efficiency of about [2] Seeberger, H.: Transistorized 10-kW VHF TV 86% is obtained. Built-in monitors Transmitter NM145E – The solid-state, broad- monitoring and band high-performance TV transmitter. News automatic switchover protect the power supply against over- from Rohde & Schwarz (1994) No. 146, current, overvoltage and overtempera- pp 4 – 6 The transmitter control unit is the switch- ture. ing center of the transmitter. It ensures the correct switching sequence of the The heatsinks (optimized by computer cooling system, power supply and simulation) for amplifier and power- control power. It also monitors air flow, supply plug-ins with a very low pressure the inlet and outlet temperature and the drop in the air flow allow the use operating status of the RF power plug- of energy-saving, low-pressure cooling ins, the power supplies and the com- systems. The inlet and outlet air can be plete transmitter. A fully integral part is routed to the transmitter top or bottom. also the automatic switchover for “passive exciter standby”, “passive transmitter standby” and “active dual output stage” with the corresponding control fields which are activated by matching front-panel plates and software.

A clearly arranged display panel allows simultaneous indication of three freely Condensed data of solid-state UHF TV Transmitter NH500 selectable operating parameters. Vision, Frequency range 470 to 860 MHz sound-1 and sound-2 power or reflected Output power, vision 5/7.5/10/15/20/30 kW vision power, reflected sound power, Output power, sound 0.5/0.75/1/1.5/2/3 kW inlet temperature, outlet temperature, Output impedance 50 Ω absorber power of diplexer, etc are Standards B/G, M/N, D/K, I (others on request) displayed. A current error is displayed AC supply 3 x 230/400 V, 47 to 63 Hz in the status line. All basic settings such RF output RL68 or RL100, depending on power as power levels, RF thresholds or tem- Reader service card 150/08 perature warning threshold of outgoing

28 News from Rohde & Schwarz Number 150 (1996/I) Articles

150-W HF Dipole HX002A1 and medium distances are especially problematic as the low frequencies used do not lend themselves to imple- The antenna for reliable menting a compact antenna. That is why rod and loop antennas have been shortwave links used up to now in many cases. The drawbacks of these antennas com- Even in the age of optical-fiber and satellite links there is a need for other pared to HF Dipole HX002A1 are illus- communication media. Experience gained from critical situations shows that even trated in FIG 2. Despite the reasonable for very broadband and powerful satellite links bottlenecks in communication gain of the rod antenna, the null in the can occur. Just as in the past, shortwave can be recommended as an information zenith of the radiation pattern prevents carrier with many advantages and with it HF Dipole HX002A1 from Rohde & high-angle radiation and the socalled Schwarz. skip zone is formed. Loop antennas,

FIG 1 150-W HF Dipole HX002A1 Photo 41 579

Offering independence from infra- Schwarz offers a 100-W class model on the other hand, may have radiation structure, providing a free transmission to go with the tried and tested An- directed upwards but efficiency and medium and given the big advances tenna HX002 for 1 kW [1]. Its main thus gain leave a lot to be desired with made in the development of secure characteristics are problem-free and regard to the available antenna sizes. transmission methods, shortwave has, cost-effective antenna installation, in many cases, become a full-value optimum radiation patterns and maxi- Low-loss dipole antennas arranged information medium. The antenna has mum reliability. horizontally at a sufficient height a major influence on the transmission above ground yield the required radi- quality. Any losses at this point of the The availability of the communication ation patterns and satisfactory gain. transmission link cannot be made up for link is of major importance for any Compact antennas of high efficiency at a later stage. That is why investments shortwave user. Antennas with opti- that are small in relation to the oper- in antennas that are state-of-the-art al- mized performance data such as ating wavelength require low-loss ways pay off. Especially in the 100-W radiation patterns and gain make a tuning networks, however, to ensure class it is very important not to waste vital contribution to fulfilling this require- matching with the feeder cable or any of the effective radiated power ment. The radiation pattern has to be with the transmitter output impedance. by using low-cost antennas. As modern matched to the time- and frequency- In systems with automatic link setup, transmission methods often operate dependent wave characteristics of the for example, these networks have to with a very large bandwidth, the ionosphere and to the orientation and be tuned fully automatically in a frac- antenna becomes more and more length of the transmission link: steep tion of a second. Broadband solutions important for obtaining sufficient takeoff angles and low frequencies are in the form of dipoles attenuated with signal/noise ratio. required for distances of up to some resistors (implemented as loaded hundred kilometers whereas flat takeoff dipole, terminated folded dipole, in- With the newly designed 150-W HF angles and higher frequencies are verted-V, delta antenna, etc) do not Dipole HX002A1 (FIG 1), Rohde & needed for longer distances [2]. Short yield acceptable gain even with

News from Rohde & Schwarz Number 150 (1996/I) 29 Articles

limited as on rooftops in heavily built- up areas. For this application Rohde & Schwarz offers 5-m Mast KM002A1. When the antenna is to be mounted above ground or on very large roof areas, 15-m Mast KM451B2 can be provided.

Rod With a bottom limit frequency of antenna 1.5 MHz the application range of the Loop antenna is greatly extended compared antenna to common high-angle HF radiators: below 2 MHz the antenna is designed to excite mostly groundwaves. Thus the availability of radio links over distances FIG 2 Spatial radiation patterns of rod anten- • single mast, of up to 100 km is further increased due na, loop antenna and HX002A1 at f = 3 MHz. • compact size, to the fact that these waves propagate Left: overall HX002A1 pattern compared to that of rod antenna. Right: patterns of loop antenna • high gain, above ground independently of the with side length of 1.4 m and HX002A1. Arrows • no control cable, conditions of the ionosphere. indicate typical propagation path for medium- • setting time <30 ms. range link. Arrow length is measure of field strength generated along this propagation path. Design All these excellent features are obtained by integrating the tuning network into The radiators as well as the automatic the feedpoint of the dipole and by using tuning unit and balun are part of the ultramodern microelectronics. Thanks compact antenna head of HF Dipole to its low weight of only 35 kg together HX002A1 (FIG 4). The tuning elements with a self-supporting single mast and of the RF section consist of a number of span of only 10 m, the antenna is ideal low-loss capacitors and air coils whose for use where the available space is values are binary-stepped. The tuning control circuit with its microprocessor core allows rapid and continuous tuning. The typical tuning time at unknown frequencies is 3 s. Tuning settings for up to 1500 frequencies are stored in a nonvolatile learn memory. The time required for repeated tuning is thus FIG 4 Block diagram of HF Dipole HX002A1 drastically reduced to typically 200 ms.

FIG 3 Gain of different shortwave antennas

3 dB Measuring unit larger antenna sizes (FIG 3) [3]. More- over, the required infrastructure such as two masts, additional foundations or tie points on adjacent buildings Modem Tuning control Relay driver often nullifies the advantage of a rela- unit tively favourably priced antenna.

Blower 150-W HF Dipole HX002A1 fully meets all the requirements. Its most important features are:

30 News from Rohde & Schwarz Number 150 (1996/I) Articles

In channel mode the previously learnt tuning settings can be set direct without retuning. In this case the setting time is again reduced to less than 30 ms.

A built-in test equipment (BITE) signals any impermissible operating state to ProcessorPC the transceiver connected. Thus the antenna can be protected against overtemperature, overvoltage and overcur- 100-W Remote transceiver control rent. The connection to the transceiver or junction unit is noteworthy: the supply voltage, high frequency and control signals are transmitted via a single one- core cable. As no additional control FIG 5 Uses of HF Dipole HX002A1 cable is required, setup of the antenna is particularly simple and inexpensive.

Use

Antenna HX002A1 can be operated is also possible via this interface. REFERENCES with practically every 100-W short- Any inadmissible operating state is [1] Demmel; F.: HF Transmitting Dipole HX002. wave transceiver (FIG 5) and especially signalled to the interfaces so that News from Rohde & Schwarz (1985) No. 112, pp 39–40 easily with Rohde & Schwarz units. appropriate actions can be taken to [2] Stark, A.: Propagation of electromagnetic Thus the antenna is the ideal comple- protect the antenna (eg RF switch-off). waves. News from Rohde & Schwarz (1986) ment to HF Transceiver Family XK200 In this way the antenna can rapidly No. 112 to 115 (refresher topic) [4] with all its benefits. For setups with and easily be integrated into existing [3] Belrose, J.S.; Royer, G.M.; Petrie, L.E.: XK852, Junction Unit GX002A1 inte- shortwave systems. HF Wire Antennas over Real Ground: Com- grates the antenna into the transceiver Franz Demmel; Axel Klein puter Simulation and Measurement. AGARD Lecture Series No. 165, 1989 operating concept. The antenna need [4] Helmke, B. ; Wachter, G.: HF Transceiver not be operated alone as it is XK 2100 – Digital shortwave for future-proof, always controlled fully automatically long-haul communication. News from Rohde by the transceiver. This also applies to & Schwarz (1994) No. 144, pp 4 –7 systems using the ALIS processor from Rohde & Schwarz for automatic link setup.

Basically, any 100-W shortwave system can benefit from the advantages of HX002A1. Junction Unit GX002A1 is the link between a non-Rohde & Condensed data of 150-W HF Dipole HX002A1 Schwarz 100-W transceiver and the Frequency range 1.5 to 30 MHz antenna. Antenna operation is then Permissible RF power 150 W PEP, 100 W CW limited to three functions: Required tuning power 50 to 100 W • triggering of tuning, (for non-R&S transmitters) • selection of receive mode (narrow- Input impedance 50 Ω band or broadband), VSWR ≤ 1.5 (typ. 1.3) • starting of selftest and display of test Tuning time new tuning typ. 3 s, repeat tuning results, ie continuous monitoring of typ. 200 ms, silent tuning ≤ 30 ms key antenna parameters. Length of dipole/weight 10.7 m/approx. 35 kg Junction Unit GX002A1 Supply battery 22 to 32 V, These operations can be performed on AC supply 100/120/220/230 V ±10% the junction unit itself, by remote control Weight 8.5 kg or from a PC via an RS-232-C inter- Reader service card 150/09 face. Silent tuning and channel call

News from Rohde & Schwarz Number 150 (1996/I) 31 Application notes

Test signals for digital television

Digital TV is coming in fast. Conven- been successfully used for a long time. given conditions, ie it has to manage tional TV receivers cannot handle digi- This type of modulation was also with a bandwidth of 8 MHz. With tal signals, so new receivers or at least chosen for satellite transmission. The QPSK modulation as used in satellite add-on equipment is needed. Develop- attainable data rate depends on the TV, a data rate of not more than 8 Mbit/s ment is in full swing at all manufacturers available transponder bandwidth of would be possible. However, since engaged in this field. Among other the satellite and on the desired error transmission on cables is as good as things, signal generators supplying de- protection of digital transmission. The free of disturbance and features an fined test signals are required. An instru- transponder bandwidth of ASTRA 1D, excellent S/N ratio, multi-level mod- ment combination suitable for this task for instance, is 33 MHz and that of ulation may be chosen. In this case is Arbitrary Waveform Generator ADS succeeding satellites will be extended 16QAM, 32QAM or even 64QAM [1] and Signal Generator SMHU58 to more than 50 MHz. To guarantee the modulation can be used, permitting with I/Q modulator [2; 3] (FIG 1). highest possible flexibility, a number 4, 5 or 6 bits to be transmitted with each modulation step instead of the 2 bits with QPSK. Thus data rates up to 42 Mbit/s can be obtained in an 8-MHz channel (FIG 3).

When digital TV signals are propagated via terrestrial TV transmitters, a combination of the problems involved FIG 1 with terrestrial DAB (digital audio Setup for test-signal broadcasting) and cable TV is en- generation countered. Multipath reception occurs for digital TV as with DAB and, in addition, the available frequencies are organized in 7- or 8-MHz channels. At present the Transmission paths for DVB of data rates ranging from 40 to over modulation modes of the two systems 80 Mbit/s have been specified in are being combined: COFDM with DVB (digital video broadcasting) sig- the standard. The wider the bandwidth, 64QAM for the individual carriers nals are propagated in three ways: the higher the achievable bit rate. The (FIG 4). As in this case the signal band- via satellite, on cable networks and higher the bit rate, the more programs width may be wider than with DAB, the via terrestrial transmitters. Since the can be transmitted simultaneously number of carriers can be increased. characteristics of the three methods (FIG 2). Up to 6785 carriers spaced approx. are so fundamentally different, three 1.1 kHz are being considered at different types of modulation standard When DVB signals are fed into cable present. Thus the data rate of about had to be specified. networks, a problem is encountered: 42 Mbit/s obtained in the cable net- existing networks have a bandwidth work can be achieved in an 8-MHz Satellite transmission basically func- of 8 MHz, which cannot easily be channel or 7/8 of it (35 Mbit/s) in a tions like transmission on a microwave changed. The new medium of digital 7-MHz channel. link. For this, QPSK modulation has TV therefore has to adapt itself to the Different signals – one solution

No matter how very different the modulation modes used for digital TV are, practically all of them can be generated with the combination SMHU58 + ADS [4]. This is made possible thanks to the flexibility of the arbitrary waveform generator. Computation of these FIG 2 Spectra of DVB signals is very complicated however. signals via satellite Here, software packages IQSIM-K and

32 News from Rohde & Schwarz Number 150 (1996/I) Application notes

FIG 3 DVB signal for cable network FIG 4 Detail of spectrum of terrestrial DVB signal (COFDM with 64QAM)

DAB-K1 provide the necessary support signals. The number of carriers to be trum of a signal generated in this way [5; 6]. Depending on whether a signal generated can be set between two and fully corresponds to that obtained with with only one modulated carrier is used 8190, the carrier spacing is freely music or video modulation. as in satellite or cable TV, or a COFDM selectable. Phase and amplitude of signal with a large number of carriers, the individual carriers can be read in For generating the broadband signals the signals are calculated by means of from a data file. Such a file is used, for required for satellite TV, Arbitrary IQSIM-K or DAB-K1. instance, to generate a DVB signal for Waveform Generator AWG2021 from terrestrial digital TV transmission. The Tektronix is available. The characteris- Software IQSIM-K is able to handle 12-bit amplitude resolution of ADS tics of this generator are very similar virtually any type of modulation for is also sufficient for future 256QAM to those of ADS and, like ADS, it can transmitting data on a single carrier: modulation of the carriers. From the be combined with SMHU58, Software FSK, PSK and, of course, QPSK and predefined phase and amplitude IQSIM-K and Software DAB-K1. 16/32/64QAM, which are of partic- values, the program calculates a signal Albert Winter ular interest here. Selectable signal waveform whose spectrum after I/Q ––– filtering according to the √cos rolloff modulation shows exactly the prede- as stipulated by the DVB standard is fined values. Of course, interference REFERENCES also provided and may be adapted can also be generated with DAB-K1. [1] Titze, H.G.: AMS and ADS – applications to modifications of the standard or For simulating fading effects, for infor state-of-the-art ARB generators. News from Rohde & Schwarz (1991) No. 135, expansions. The capability of impress- stance, a certain number of carriers can pp 25–27 ing interference onto the normally very be suppressed or a random amplitude [2] Lüttich, F.; Hecht, A.: Signal Generator clean modulation signal may be of or phase error be impressed. A special SMHU58 with I/Q modulator. News particular interest for development problem area with these signals is am- from Rohde & Schwarz (1991) No. 132, labs, eg the superposition of noise for plitude peaks of brief duration, whose pp 8 –11 BER measurements or the generation of clipping can be simulated. [3] Winter, A.: Test-signal generation for digital audio broadcasting using Generators modulation errors as may be caused SMHU58 and ADS. News from Rohde & by non-ideal I/Q modulators of trans- For simulating a sequence of COFDM Schwarz (1992) No. 139, pp 24 –25 mitters. Thanks to versatile analyzing symbols as transmitted in sound and [4] Application Note 1GPAN27: Test signals capabilities like spectrum display of the TV programs, several symbols are com- for digital audio and digital video broad- modulated signal, eye pattern, vector puted consecutively and stored in ADS. casting display or display of I/Q signals, mod- Up to 25 different symbols (or alto- [5] Winter, A.: Simple generation of COFDM signals with Software DAB-K1. News ulated signals can be simulated already gether 64k data words) can be saved. from Rohde & Schwarz (1994) No. 145, on a PC. After transfer to ADS, they are The symbols are then organized in a pp 28 –30 available for modulating SMHU58. sequence in which the same symbol [6] Winter, A.: Band-occupancy simulation may occur several times. With DAB-K1, with Signal Generator SMHU58 and ADS. COFDM signals for terrestrial digital random symbol sequences can also be News from Rohde & Schwarz (1995) No. 147, pp 36 –37 TV require completely different compu- generated. The sequence is transferred tation and handling. Software DAB-K1 to ADS and the individual symbols are was therefore developed for these called up one after the other. The spec- Reader service card 150/10

News from Rohde & Schwarz Number 150 (1996/I) 33 Application notes

BER measurements with Base-Station Test System TS8510

the parity bits to determine the quality of the data and in the case of an irre- coverable error among the class Ia bits rejects the entire frame. The receiver replaces the rejected frame by an inter- polated expectancy value.

According to the GSM specification, the following bit-error-rate measurements are to be performed in the traffic channel: bit error ratio (BER)

BER = bf/bo bf being the number of errored bits and bo the total number of bits,

frame erasure ratio (FER)

FER = fbfi/fo fbfi being the number of rejected frames and fo the total number of frames, FIG 1 Test System TS8510 for GSM/PCN base Receiver measurements play a critical stations Photo 41 749 role in the development and approval residual bit error ratio (RBER)

of base stations as the quality of the re- RBER = bfok /bok ceiver is the main factor that determines bfok being the number of errored bits in the quality of a base station. With ana- frames that have not been designated

log networks the quality of a receiver is as errored and bok the total number of determined by measuring the signal/ bits in good frames. Test System TS8510 was designed for noise ratio or total harmonic distortion type-approval tests on GSM and PCN of the demodulated wanted signal; with Besides BER measurements in the traffic base stations [1]. The tests are de- digital networks, on the other hand, the channel, the GSM specification also scribed in GSM specifications 11.21 bit error rate before D/A conversion is defines BER measurements in signal- and 11.23 (GSM spec. 11.21 contains measured. This poses a difficulty in ling channels. These measurements RF and link-management tests, GSM GSM and PCN networks, because on- are performed by comparing bits in spec. 11.23 signalling tests). Digital ly bits that represent the wanted signal or after the receiver. It is assumed in Radiocommunication Test Set CRTP04 are used for measuring the bit error the specification that base stations are [2] is the main component of the rate. GSM networks transmit 456 bits equipped with special test interfaces; system. As a signalling unit, it is respon- in a 20-ms frame but only 260 bits these interfaces, however, are usually sible for setting up calls with the base represent the wanted signal. 182 of the provided by different manufacturers station and its two signal sources simu- 260 wanted signal bits use redundancy and are, therefore, not suitable for a late the traffic channel and a GMSK- for error control, only 78 bits are trans- universal test system. If these tests are modulated spurious signal. After call set- mitted without error protection. The carried out on the Abis interface, spe- up, CRTP04 measures the power ramp, other 196 bits are used to detect and cial test interfaces are not necessary. phase error and bit error rate. CRTP04 correct errors. In GSM parlance one One should be aware of the fact, how- also acts as a system controller. The refers to class I bits (protected bits) and ever, that at this interface bit errors other components of the system are a class II bits (unprotected bits). Within have already been corrected. In order spectrum analyzer, a fading simulator, class I, a distinction is made between to obtain meaningful test results, error two signal generators for the genera- class Ia bits and class Ib bits. In addition correction at the base station needs to tion of interfering signals, an RF switch- to convolutional coding for all class I be switched off, as otherwise only ing matrix, a power meter for path com- bits, class Ia bits are also protected unprotected class II bits are available pensation and a protocol tester. by three parity bits. The receiver uses for measuring bit error rate.

34 News from Rohde & Schwarz Number 150 (1996/I) Application notes

In BER measurements as performed CRTP04 for evaluation. The bit error ated at the wanted signal’s frequency by Test System TS8510, the data rate must not exceed 0.0001%. The +200 kHz and its level 9 dB higher. stream received by the base station is level of the wanted signal is increased In a further test, the interfering signal’s fed to the base-station transmitter and step by step up to –15 dBm. A bit offset is 400 kHz and its level 41 dB then back to the test system. Loopback error rate of up to 0.001% is permitted. higher than that of the wanted signal. takes place either at the Abis interface The last step is to loop back the signal or in the receiver unit still before error through the fading simulator, the maxi- The Blocking test case (FIG 3) is very correction (FIG 2), if such is allowed mum bit error rate now being 3%. demanding both for the device under by the base station. In the latter case test and the test system. The wanted one has to differentiate between two If only the wanted signal is available for signal generated by CRTP04 has a loopback modes: in one mode data the Static Layer 1 Receiver Functions level of –101 dBm. The blocking signal are looped back without bad frame test of a base station, one or more inter- is generated by the microwave gen- detection, in the other the bits of a fering signals are added to the wanted erator of TS8510. With frequencies rejected frame are set to zero and sent signal for further tests. For the Static between 100 kHz and 12.75 GHz the to the test system via the base-station Reference Sensitivity test CRTP04 transmitter. CRTP04 determines BER, generates a wanted signal with a level FER and RBER. This arrangement also of –104 dBm. In the adjacent time slots allows BER measurements in signalling of the wanted signal, two interfering Notch filter channels, provided the base station signals whose levels are 50 dB high- Blocking signal has a suitable loopback. Before each er are generated by RF Generator +8 dBm

BER test, the signal path leading from SME03. The RBER of class II bits must Level the Abis interface via the base-station not exceed 2%. transmitter to the CRTP04 receiver is tested to ensure that all data on this Reception conditions are even stricter Noise floor blocking signal signal path are transmitted without bit for the Multipath Reference Sensitivity Frequency errors. Conditions test. In this test the wanted signal is degraded by the fading FIG 3 Blocking test with Base-Station Test GSM specifications stipulate several simulator. The bit error rate is measured System TS8510 bit-error-rate measurements on base by CRTP04 using the fading profiles stations. The Static Layer 1 Receiver Typical Urban 50 km/h, Rural Area Functions test is for measuring bit error 250 km/h and Hilly Terrain 100 km/h. rate under “ideal” conditions. For this The maximum permissible RBER of level is +8 dBm. This test requires a test the level of the signal generated by class II bits is between 7% for rural area signal with a particularly good S/N CRTP04 is around –80 dBm. The base and 9% for hilly terrain. ratio. The measurement bandwidth of station operating in loopback mode the base-station receiver is 200 kHz. sends the received signal back to The Reference Interference Level test At an input bandwidth of 200 kHz, case measures a receiver’s immunity the noise power per 1 Hz is to EMI with the wanted signal and 10 Iog (200 kHz/1 Hz) = 53 dB. interfering signal at the same frequency. The required S/N ratio is obtained as The level of the interfering signal gener- follows: 8 dB – (–101 dBm) + 53 dB ated by the RF generator is 9 dB lower + 10 dB (margin) = 172 dBc. than that of the wanted signal gener- This extremely high S/N ratio is

FIG 2 Loopback modes for BER measurements: ated by CRTP04. The test is repeated achieved by a notch filter incorporated at Abis interface (left) or in base station (right) with the interfering signal being gener- in TS8510.

The Intermodulation Characteristics test case verifies the linearity of the base-station receiver. The composite signal is made up of a wanted signal of Digital Radio- Send data Digital Radio- Send data communication communication –104 dBm and two interfering signals RF stage Receive data RF stage Test Set Receive data Test Set CRTP 04 CRTP 04 of –43 dBm. The intermodulation products of the interfering signals are

Protocol and Protocol and superimposed on the wanted signal. Protocol tester Protocol tester A interface Abis interface signalling bis signalling The RBER of the class II bits measured unit unit by this test must not exceed 2%.

News from Rohde & Schwarz Number 150 (1996/I) 35 Application notes

The signals used for all receiver tests One channel is used to monitor REFERENCES must have accurately defined levels. transmission levels, the other to moni- [1] Tiwald, W.: Type-approval tests on This is ensured by a complex RF tor receive levels. These test probes GSM/PCN base stations with Test System TS8510. News from Rohde & Schwarz switching matrix. It filters, mixes, am- determine reference values to auto- (1993) No. 143, p 28 plifies or attenuates the signals. Two matically compensate for level errors [2] Schubert, W.: Digital Radiocommunication RF test probes are incorporated at that occur when the tests are being Test Set CRTP04 – Test set for base stations crucial points of the switching matrix run. to new PCN/DCS1800 mobile-phone stan- to minimize frequency dependence. Michael Manert; Wilfried Tiwald dard. News from Rohde & Schwarz (1993) No. 143, pp 8 –10

Reader service card 150/11

Loudspeaker measurements with Audio Analyzer UPD

Development and production of top- quality loudspeakers and enclosures are impossible without a fast and reliable audio tester that generates all necessary signals (noise, sinewave, burst) and measures the response of electrical and acoustic components. Loudspeaker measurements using Audio Analyzer UPD from Rohde & Schwarz [1] are supported by an application program which can be loaded and started directly under the UPD software (FIG 1), provided UPD is fitted with option UPD-K1 [2]. This means that all UPD functions can be called in the usual way even when the application is running. This program adds special tests and computing routines for loudspeaker FIG 1 Audio Analyzer UPD for loudspeaker After the application program has measurements to existing UPD func- measurements in sound studios been started, the entire operation is Photo 41 751/7 tions: by softkeys that resemble UPD controls • measurement of impedance and de- or via keyboard entries in dialog rived parameters to IEC 268, part 5, the characteristics of a reference loud- mode. Every softkey operation can • sound-pressure measurement (fre- speaker and the tolerances (go/nogo be memorized and repeated (macros) quency range, efficiency and angle test). so that measurements can be com- of radiation), bined in any number of ways – real • phase response and group delay, Impedance and sound pressure can help with production testing for in- • harmonic-distortion measurements, be measured in different ways, with stance. By pressing a softkey the • polarity measurements. measuring time or precision optimized user can temporarily switch over to as appropriate. The test setup must UPD operating software to scale The program is equally well suited for include a power amplifier and a pre- and label graphics for instance, and use in development labs or production cision test microphone (except for im- then return to the application pro- environments, for instance by defining pedance measurements). gram.

36 News from Rohde & Schwarz Number 150 (1996/I) Application notes

For impedance measurements the im- 3. Frequency sweep with burst signals; the application software. However, the pedance versus frequency character- preferred application: far-field meas- measured phase difference between istic is recorded and all relevant im- urements (even in non-anechoic cham- two adjacent sweep points may not pedance values and parameters such bers). The burst generator included as exceed 180°. The application software as a loudspeaker’s Q and equivalent standard in UPD is used for a specially automatically ensures that this condi- volume are calculated (FIG 2). Since programmed sweep which measures tion is met by calculating an appro- UPD is equipped with a DC generator only the first period of the sound wave. priate frequency increment on the basis and DC test function, resistance can be of the microphone distance that has measured without using any additional With both sweep measurements, the been entered. equipment. Resonance impedance, lower and the upper frequency range resonance frequency and tuning fre- can be measured separately at differ- To make linearity errors easier to see on quency are derived from the imped- ent microphone distances, and the the screen, the phase response can ance characteristic. Q and equivalent near-field and far-field curves can be also be displayed as linearity deviation volume are calculated to IEC 268, combined at a transition frequency or group delay. If a reference DUT is part 5. UPD graphics functions provide selected numerically or graphically. used to compare the measured phase the absolute impedance minimum and at a fixed frequency, any reverse polar- maximum. Linear frequency sweeping is recom- ity condition can be detected (reference mended for phase-linearity measure- and DUT are 180° out of phase). As the The sound pressure versus frequency ments. The phase between loudspeaker microphone distance for the reference characteristic (FIG 3) can be used to input and output sound wave is meas- and the DUT must be the same to with- evaluate loudspeaker sound quality, ured. A linear phase response (ideal in a certain degree of accuracy, this shows whether the crossover networks case) is a straight line. To obtain a con- method of checking polarity is best for are dimensioned correctly and also tinuous phase response without jumps low frequencies. detects if the polarity of any speaker of 360°, the sweep points measured by unit has been reversed. Measuring the UPD from 0° to 360° are processed by The following types of total harmonic sound pressure at a fixed frequency distortion can be measured and dis- yields the maximum sound pressure played: THD total, THD d2, THD d3 (at rated power) and the sensitivity (at and THD+N. It is possible to display 1 W). Sensitivity is required in turn as a both the distortion at a fixed frequency reference for the 0-dB line of the trans- and the distortion frequency response fer function and the 0-dB point for deter- as a bargraph (set of single measure- mining the radiation angle. ments), as a curve representing the frequency response or as a frequency There is an automatic routine for setting spectrum of the harmonics (FFT). output power. Depending on nominal Martin Schlechter loudspeaker impedance, this routine adjusts the generator level until the output power is obtained.

FIG 2 Impedance characteristic with test report The measurement can be performed in (resonance frequency and impedance, resistance, three different ways: Q, etc)

1. FFT analysis of a special pseudo- random noise signal; preferred application: fast measurement of the entire REFERENCES frequency range, eg in production test- [1] Kernchen, W.: Audio Analyzer UPD gener- ing. ates and measures analog and digital audio signals. News from Rohde & Schwarz 2. Frequency sweep with sine signals; (1992) No. 139, pp 13 –15 preferred application: measurements [2] Hempel, J.: Automatic audio measurements under free-field conditions (eg in an with user-friendly control system of Audio Analyzer UPD. News from Rohde & Schwarz anechoic chamber) and near-field (1993) No. 143, pp 29–30 measurements, ie wherever sound reflections do not occur or can be ne- FIG 3 Frequency response and calculated fre- glected. quency range of loudspeaker (to IEC 268, part 5) Reader service card 150/12

News from Rohde & Schwarz Number 150 (1996/I) 37 Application notes

Signal Generator SME for tests on ERMES, FLEX and POCSAG pagers

is sensitivity measurement. Here the data protocol, eg the pager address or quality standards are determined by message contents and further network- system specifications and the quality specific information. aimed at by manufacturers. For example, an ERMES pager fulfils the stan- POCSAG

POCSAG Differences between dard sensitivity requirements if it cor- pager systems rectly recognizes eight of ten calls received at a field strength of 25 dBV/m Each of the three systems transmits FLEX

FLEX (80% call reliability). Fluctuations in tone-only, numeric and alphanumeric production tolerances make it neces- messages. But the systems still differ ERMESERMES sary for manufacturers to provide a considerably from one another (see safety margin, ie produce pagers with blue box). sensitivity higher than stipulated so as to reliably fulfil standard requirements. POCSAG, which originates from Great Britain, is a widely used system. In Germany it is used for Cityruf, Scall and others. Since POCSAG pagers operate at a fixed frequency, the radio networks employ the time-slot method: transmitters change frequency in a cycle FIG 1 of up to two minutes so that different Signal Generator frequencies are used in adjacent trans- SME, expert for mitter zones. Within a zone, transmit- all pager systems ters operate on a common frequency. Depending on the country, frequencies between 450 and 470 MHz are used. The transmission protocol is of a com- More and more new systems are estab- Another test is concerned with the paratively simple structure. The trans- lishing themselves not only in digital recovery of synchronization. This is mission of messages is not bound to a mobile radio but also on the pager the capability of a pager of restoring fixed time pattern. A transmission can market. Examples are ERMES [1] (Euro- the required synchronization with the be started any time, so the pager must pean Radio Message System) and transmitted signal after a brief inter- listen all the time if it is not to miss a call. FLEX [2], which are used in addition ruption of reception. In accordance The words of a message are protected to POCSAG [3] (Post Office Code with FTZ guideline 171TR1 (Cityruf) by checksums. To compensate for inter- Standardization Advisory Group) set (FTZ = Research and Technology ference lasting longer than a message up in 1979 and known in Germany Center of German Telekom), the pager word, a message can be repeated up under the name of Cityruf [4]. Common is sent test modulation with the level re- to three times. to these systems is unidirectional com- duced by 40 dB relative to the signal munication from the transmitter to the level for a specific time (FIG 2). The FLEX was developed by Motorola pager, which does not acknowledge pager must still be able to receive calls from 1993 onwards. Compared with the receipt of a message. Of course all without losing synchronization with the POCSAG, particular emphasis was pagers must be tested in development, transmitted signal. placed on more efficient utilization production and service. For this Rohde of channels, enhanced transmission & Schwarz offers Signal Generator Signal Generator SME provides the reliability and low energy consumption SME (FIG 1), which is able to supply appropriate signals for both tests with- by the pager. It is possible to use the required signalling for each of the out any additional external equipment. POCSAG transmitters in the FLEX above systems. Convenient operating menus assist the system with only minor modifications. user in generating a message to the The two systems can even be combined An essential test that has to be per- pager. SME requires just a minimum of to operate in time multiplex. FLEX uses formed irrespective of the system used information to generate the complete FSK with two or four states, resulting

38 News from Rohde & Schwarz Number 150 (1996/I) Application notes

Data content ERMES, unlike POCSAG, does not POCSAG use time slots but frequency-division • Bit rates of 512, 1200, 2400 bit/s, Pre- 1st 2nd 3rd 4th 5th 6th 7th amble batch batch batch batch batch batch batch multiplex. The ERMES standard defines • FSK and FFSK modulation, 16 channels and 16 classes of receiver. • selectable frequency deviation, Reference As with FLEX, transmitters operate • selectable time-slot duration.

Level within a fixed time pattern coupled to the time of day. Messages are trans- FLEX mitted in a time window of 750 ms for • Setting of all important network and FIG 2 Signal for testing recovery of synchronization with Cityruf in compliance with FTZ guide- each class of receiver, then changeover system information, line 171TR1 is made to the next class. Each channel • all types of message available, in- starts with a different class of receiver, cluding special numeric, secure and so in case of a fully featured transmitter binary messages, system a pager can receive messages • on request, automatic adaptation for its class at any time by changing of transmission parameters with in a data rate of up to 6400 bit/s. To channel every 750 ms. This system change of CAPCODE, increase transmission reliability, the makes greater demands on the re- • all three bit rates (1600, 3200 and messages (with checksums) are inter- ceivers but enables flexible expansion 6400 bit/s) and both modulation leaved: the first bits of all words are of the network from one up to 16 trans- types (2FSK and 4FSK) selectable, sent first, then the second bits, and so mitters per zone, with all pagers • simulation of time slots with data on. Interference of reception extending profiting from the additional trans- from other transmission systems, over several dozens of bits is thus dis- mitters provided. Like in FLEX, the bits • emergency resynchronization, tributed to all words of a message and of the message words are interleaved • allowance for cycle number during corrected by means of the checksums. in the ERMES system to improve trans- transmission, ie signal in line with mission reliability. standard over one hour. FLEX transmissions are rigidly coupled to the time of day. A new cycle is started One signal generator ERMES every full hour. Messages for individual for all pager systems • Setting of all important network addresses are sent at defined times and system information, within a cycle. This means that a pager, Signal Generator SME supplies tone- • deliberate corruption of bits of once synchronized, needs to be ready only, numeric and alphanumeric mes- message words, for reception only for a fraction of the sages for each of the three paging • free selection of receiver class to cycle without any messages being systems. As to alphanumeric messages, which message is sent. missed and can thus save battery SME provides memory capacity for power. Moreover, date and time of day three predefined and three user-defin- With the above features, Signal and also binary data transparent to the able message texts. Switchover can Generator SME is an unrivalled signal receiver can be transmitted with FLEX. be made between filler data and mes- source for all pager systems. The In conjunction with a computer, this sages on a keystroke or by an external flexible instrument concept allows con- would enable FLEX to receive current trigger. SME offers the following spe- venient and cost-effective integration stock-market prices for example. cial features for each system: of a wide variety of data protocols used in today’s pager systems plus support for future systems. Mathias Leutiger; Daniel Schröder

REFERENCES Pager system POCSAG (Cityruf) FLEX ERMES [1] ETSI TCPS: Paging System (PS); European Ra- Transmit frequency 3 frequencies, Not definded 16 channels, dio Message System (ERMES), ETS 300 133 465.970 to 466.230 MHz 169.4125 to 169.8125 MHz [2] Motorola Paging Group: FLEX™ Protocol Modulation FSK with 2 states FSK with 2 or 4 states FSK with 4 states Specification G1.7, 1995 Data rate 512 to 2400 bit/s 1600 to 6400 bit/s 6250 bit/s [3] British Post Office: A Standard Code for Number of addresses 221 per frequency Approx. 109 per network 222 per network Radiopaging (POCSAG), 1979 operator operator [4] German Telekom: Cityruf, Funkrufempfänger, Area of use Europe USA, Asia Europe (being built up) betriebliche und technische Merkmale. Options required in DM Coder SME-B11, DM Coder SME-B11, DM Coder SME-B11, FTZ 171TR1, 1991 Signal Generator SME Memory Extension Memory Extension Memory Extension SME-B12, POCSAG SME-B12, FLEX Option SME-B12 Reader service card 150/13 for further infor- Option SME-B42 SME-B41 mation on SME

News from Rohde & Schwarz Number 150 (1996/I) 39 Application notes

Interference analysis in digital mobile-radio networks

Co-channel and adjacent-channel inter- permanent or traffic-dependent inter- Measurement procedure ference is the major source of distur- ference depending on the type of bance in digital mobile-radio networks channel. All interference measurements A measurement with the interference to GSM standard. Various measures refer to the downlink, ie the link from analysis system is equivalent to the can be taken to eliminate this type of the base station to the mobile phone. identification of one or more bicycle lamps amidst 100 car headlights as seen with the naked eye within 0.5 s from a distance of 200 km. This comparison applies to the determination of the nominal power and the identification of the BCC (base-station colour code) of a base station often several cells away, which may cause interference in another mobile-radio cell due to its channel occupancy. The nominal power is the power of the radio waves of the base-station BCCH at the site of measurement and forms the basis of the interference measurements (FIG 2). In the above scenario, the car headlights are the occupied traffic or signalling channels which use the same frequency and belong to the examined or an adjacent base station as well as other interference which complicates analysis of network- FIG 1 Digital Radio Analyzer PCSD as core of The downlink measurement has priority specific interferers. Interference Analysis System PCSD-K1/K11 since base stations are generally Photo 42 147 less susceptible to interference and In stationary measurements (software can change frequency if interference option PCSD-K1) up to 640,000 becomes too strong. samples of the IF signal are taken for nominal-power measurement and BCC identification and analyzed within interference once it is localized. Rohde Hardware components of a few seconds by means of special & Schwarz offers the right test and meas- interference analysis system signal-processing methods and spe- urement product for this purpose. Inter- cially developed algorithms for pattern ference Analysis System PCSD-K1/K11 Options allow the interference analysis recognition. Pattern recognition can combines sensitive RF measurement cir- system to be configured for various ap- detect several BCCHs on one channel cuits with high-performance processors plications. The basic version comprises with power ratios up to 40 dB. A prob- and algorithms to detect and analyze Digital Radio Analyzer PCSD (FIG 1), ability analysis of the BCCs allows • co-channel interference, which includes a complete PC, a three- detected BCCHs to be allocated to one • adjacent-channel interference, channel 12-bit A/D converter board or sometimes several base stations. • reflection, and a board with the proven i860 Using optimized null-space projection • noise power, vector processor. The RF section con- the nominal power of potentially inter- • narrowband interference, sists of Test Receiver ESVD, which fering base stations is determined with • power density spectra, features the low phase noise required a sensitivity of –135 dBm. • power in the broadcast control chan- for interference measurements. This nel (BCCH). basic version enables the full range In mobile measurements (software of interference measurements in sta- option PCSD-K11) one to three inter- With co-channel and adjacent-channel tionary applications. For mobile use ferers can be tracked simultaneously interference the network-specific inter- the basic version can be extended by depending on the system configuration. ferer is identified and classified as a GPS receiver. A high-resolution stationary measure-

40 News from Rohde & Schwarz Number 150 (1996/I) Application notes

ment is always carried out before a only if there is really information to be available. Another interesting way mobile measurement to select the inter- transmitted. Time and power distribu- of avoiding an area with lots of ferer and ensure synchronization. The tion of traffic-dependent interference interference is by manipulating the BCCH power of the interfering base furthermore depend on network pa- handover parameters of a base station. stations is determined continuously rameters such as frequency hopping Depending on its distance from the throughout the entire test route. The (FH), power control (PC) and discon- mobile phone, the base station decides GPS receiver provides the system all the tinuous data transfer (DTX). The ratio whether to hand over the call to another time with site and motion information. between co-channel and adjacent- station or not. The mobile measurement does away channel interference corresponds to with any ambiguity in interferer identifi- that of BCCHs. For the sake of clarity, cation, which occurs rarely in station- normalized traffic-dependent interfer- ary measurements if BCCH and BCC ence is displayed which is referred to are identical, since it uses site-related the BCCH transmit power in the allo- signal-delay comparison. cated traffic channel. Without power control this interference differs from The possibility of power measurement permanent interference only in that it on and identification of BCCH carriers occurs less frequently. Measures such opens up the following concept for as FH and DTX reduce the probability measuring co-channel and adjacent- of transmission impairments caused channel interference. From a fre- by traffic-dependent interference. quency-occupancy table containing the base-station data of an investigated Advantages of the measurement con- region, the system automatically selects cept: at the site all frequencies at which • The measurement is carried out BCCHs are sent by certain base sta- without manipulations on the net- tions. Due to their channel occupancy work and independently of the net- FIG 2 Interference power measurement and such base stations can give rise to co- work parameters PC, FH and DTX. BCC identification of interfering base stations channel or adjacent-channel inter- • The measurement is not related to take place in automatically selected BCCHs. Signals of different interfering base stations can ference in at least one channel of the traffic-dependent interference the be isolated for each channel. carrier station and in addition lie within occurrence of which would other- a predefined maximum distance. The wise have to be waited for. The nominal power and its source are de- normalized measurement allows termined by stationary or mobile meas- traffic-dependent interference to urements on the selected frequencies. be determined and eliminated. • The measured data enable ade- For identifying the interference, a dis- quate evaluation of new channel Network optimization tinction is made between whether a allocations as well as detection of measured BCCH or another traffic free channels. The interference analysis system is also channel has caused the interference. suitable for optimizing and extending If the BCCH itself is the interferer, a low-interference network. There are the interference is permanent since Eliminating interference two possible ways of doing this. The BCCHs continuously emit a constant first one allocates another radio chan- power level. In the case of co-channel The most simple method for eliminating nel to the specific base station. This interference the interference power is interference is changing the channel channel should cause minimum inter- equivalent to the measured nominal allocation or switching the channel off. ference in other cells and should not power, whereas with adjacent-channel For frequency economy, however, it is be subject to interference. Before the interference it corresponds to that part better and also common practice to use channel is used, it is entered into the of the nominal power that results from sector antennas and to adapt the tilt of regional frequency-occupancy table the transmitter GSM spectrum and the the antenna. The analysis system can for the test system. An evaluation of input filter of the mobile phone. check the antenna setting by means the nominal powers measured will of a stationary measurement. The high immediately inform the user about all However, if a traffic channel has dynamic range and sensitivity of the the potential interferers for this channel. caused the interference, the interfer- system are particularly advantageous The second method is based on com- ence is traffic-dependent since RF for this application since a measure- prehensive frequency planning. The power is emitted on traffic channels ment margin of more than 20 dB is system determines the nominal power

News from Rohde & Schwarz Number 150 (1996/I) 41 Application notes

of all base stations throughout the they can be entered in the appropriate entire region across cell boundaries. windows. During the measurement The measurements are performed in the user can switch from one window to the operating network and provide the another. Interference is displayed in latest coverage data for the planning three windows which show permanent, software of the network operator. This traffic-dependent and summary inter- software evaluates the results to opti- ference. Clicking the info button will mize the network. show all interference according to type and source (FIG 3). The results can be Operation and results evaluated by means of the measure- FIG 3 C/I ratio of used base-station channels ment system or any PC without any (green = permanent, blue = traffic-dependent, The system features an MS Windows hardware extension. red = summary). The info button gives access to user interface. In addition to detailed a list of all measured interference sources of the Otmar Wanierke definition of all test parameters, the channel in question. system provides easy-to-use prepro- grammable measurement routines: • nominal power measurement on all channels, Such standard measurements are se- • detailed interference measurements lected via a single menu item. Should for a specific base station. additional test parameters be required, Reader service card 150/14

Longterm monitoring of digital serial video signal using Digital Video Component Analyzer VCA

In digital TV studios, pictures are passed among the various items of studio equipment in the form of data bits. Digital transmission is quite different to analog transmission: if analog transmission errors occur, the degradation in picture quality is proportional to the number of errors. With digital transmission, however, there is no percep- tible reduction in picture quality until a certain bit error rate is reached. Only when this rate is exceeded – just one or two extra errors may be sufficient – does the quality suddenly drop. As a worst-case scenario, there may be a loss of sync and the picture disappears completely. This is where test technology comes into its own as it can provide a way of continuously monitoring the quality of digital serial video transmissions. Digital Video Component FIG 1 VCA and PC performing digital serial video-signal monitoring round the clock Photo 42 331

42 News from Rohde & Schwarz Number 150 (1996/I) Application notes

Analyzer VCA, developed by Rohde & program (eg MS Excel) to provide uring). The halt time is marked red and Schwarz, fully meets these requirements statistics or a better overview. If you can be taken into account at any later as it monitors the video signal in time really want each and every error time stage of analysis. windows of approx. 10 seconds [1; 2]. stamped and documented, use “Create ASCII error list”. This gives a clear over- The serial interface of the PC is con- Longterm, continuous monitoring is view of that part of the measurement figured in the Interface menu. The PC also required for errors that occur which is of interest. configuration and the VCA configura- only rarely. When, say, a film is copied tion must be the same. If not, the PC from one tape deck to another, the If transients of long duration are and the VCA will not be able to com- copy must be error-free. Visual inspec- involved, it is often a good idea to municate and an error message will tion would also take a considerable increase the measurement time. VCA be output. number of man hours (eg 2 to 10 h). uses intervals between 2 and 10 s This difficulty can be overcome by inte- depending on the number of fields to The cursor functions make it easy to grating VCA into a test and monitoring be measured. This time window can be find measured bit errors rapidly. Three system specifically designed for this increased to 1 to 60 min. with “Create cursor functions are available: go one purpose. VCA remote monitoring, a ASCII dataset”. This creates a table pixel to the right or left on the screen, Windows application supports digital which can be graphically processed scroll one page to the right or left and video-signal monitoring around the later using a database program. It is place cursor on the next error before or clock thanks to the VCA measurement after the current time. With the latter functions TRS (timing reference signal) function the whole measurement is and RCE (reserved code error) used automatically checked for errors. This to check the sync frame of the digital is especially important for longterm video signal. This measurement cannot measurements in which only a few find every bit error but it can be per- errors have occurred. formed on live signals, ie on moving Martin Flach pictures. As an alternative the application provides a CRC (cyclic redundancy check) monitoring function for digital stills to detect sporadic bit errors in the active picture area.

The hardware requirement is a PC with the MS Windows operating FIG 2 Evaluation of longterm measurement system and a VCA with a remote- with error cluster at 10.50 h. Cursor function control option (FIG 1). The values makes it easy to find times when errors occurred. measured by VCA are read by the VCA remote monitoring program via the serial RS-232-C interface and processed so that the total number of errors is shown on the history display (FIG 2). then possible to display the transient REFERENCES Moreover, the individual errors are response (of special interest when [1] Weigold, H.; Rohde, W.: Digital Video Com- listed on the error-rate display and developing studio equipment) in a way ponent Analyzer VCA –Waveform monitor the measured values are stored in a that is easy to understand. and signal analyzer for digital video signals to CCIR 601. News from Rohde & Schwarz file with a predefined name. (1994) No. 145, pp 8 –10 In the Measure menu, the measure- [2] Osterloh, G.: Analysis of digital transport The File menu contains a number of ment functions (TRS, RCE or CRC) are layer with Video Analyzer VCA. News useful functions to process measure- started by selecting the measurement or from Rohde & Schwarz (1995) No. 149, ments. Previous result protocols can be by clicking the appropriate icon. The pp 40 –41 displayed again and checked with the user is then asked for the size of the cursor using the “Load old result” func- measurement window, the video-signal tion. The functions “Create ASCII error standard (525 or 625 lines) and the list” and “Create ASCII dataset” trans- file name. The measurement is stopped form the result protocols into different by clicking the stop icon. A stopped

ASCII tables so that the measured measurement can be continued by Reader service card 150/15 for further infor- values can be analyzed by a database pressing the Cont icon (continue meas- mation on VCA

News from Rohde & Schwarz Number 150 (1996/I) 43 Application notes

Measuring all TV RF and video parameters for the first time in a compact unit

The main features of the TV test receiver are: • frequency range from 47 to 862 MHz, • 50- or 75-Ω input, • IF input and IF output, • video and audio outputs, • large dynamic range (40 to 120 dBµV), • low-noise and low-distortion mode, • low-noise preamplifier can be added to improve noise figure of receiver, • video S/N ratio (weighted at 66 dBµV) >56 dB,

FIG 1 • intercarrier ratio (weighted) >46 dB, Video Measurement • channel and frequency search, System VSA supports • synthesizer with low phase noise and special test require- high frequency resolution (1 Hz), ments of TV transmitters and cable • digital frequency control, systems with the aid • manual and automatic gain control, of built-in test-receiver • integrated zero clamping for defin- option (configuration ing vision modulation depth, menu of test receiver displayed) • selectable synchronous detector Photo 42 329/2 mode with sampled or continuous phase control as well as selectable time constants, • sound demodulation according to IRT dual-sound carrier method, Different measuring instruments such an ideal compact unit for standards • linear distortion of video frequency as TV test receivers, TV oscilloscopes, B/G, D/K and I. The option not only response <0.5 dB (luminance/ video monitors and video analyzers saves space but also does away with chrominance error <±20 ns), are required for quality assurance the complete cabling which is other- • video group-delay correction of and reliable monitoring of TV cable wise required. Thanks to its excellent receiver and sound deemphasis networks and terrestrial transmission performance data and the great num- can be switched off, equipment. If monitoring is to be ber of system interfaces as well as the • sound monitoring via loudspeaker carried out by means of an automatic measurement and controller functions of basic unit, system, a process controller is required of the basic unit, all standard appli- • built-in microprocessor for receiver for controlling these units. For the cations as well as customer-specific control. user this means high investment costs solutions can easily be implemented. and space requirements which are Unattended CATV system monitoring, The microprocessor which controls the not always available in mobile appli- remote polling of measurement results, complete range of receiver functions cations. With Video Measurement automatic activation of standby equip- collects continuously all the relevant RF System VSA, which integrates all ment during a transmitter breakdown data of the input signal. These data are the measuring units mentioned includ- or uses in laboratory and service en- then available as additional measure- ing a process controller in a single vironments, quality assurance and ment parameters in the VSA measure- unit (see News No. 147), Rohde & production monitoring of TV consumer ment list and are also part of the VSA Schwarz now offers, together with Test units are all possible with this powerful test report. The following parameters Receiver Option VSA-B10 (FIG 1), team of VSA with its option VSA-B10. are measured:

44 News from Rohde & Schwarz Number 150 (1996/I) Application notes

RF Audio FIG 4 • vision carrier power and frequency, IF IF Video Monitoring cable • vision/sound power and frequency TV transmitter or broadband cable network using system ratios, Video inputs Video Measurement Test Receiver LCD display Option DUT • FM deviation of sound carrier and VSA-B10 System VSA with pilot tone, test-receiver option • pilot-tone frequency and coding, Full-field memory MUX • modulation depth of vision carrier (residual carrier), Signal processor (measurement functions) • vision-carrier phase modulation. External System control (IEC 625) monitor MUX

IEC/IEEE DOS processor The important measurements of vision- bus Ext. keyboard carrier phase modulation and residual Hard- carrier required for TV transmitter disk LPT1 COM1 COM2 alignment are performed in VSA by Programs means of a single measurement (FIG 2). and test data Printer Modem Mouse The external cabling that used to be required as well as corresponding interface problems now belong to the past thanks to the compact unit VSA with integrated Test Receiver VSA-B10.

All VSAs are equipped as standard for by the user or through a Rohde & sound channel, search threshold are later installation of the test receiver. Schwarz service center. No modifica- set in the Set RF/IF Config menu. The The test receiver can be installed direct tion of the basic unit or system software Set RF Channel Definition menu is is required. The built-in test-receiver op- used to define the channel table used. tion is detected when VSA is powered The user can change freely the fre- up. The corresponding control menus quency, program names and channel are then automatically available. designations of each of the maximum 150 receive frequencies of a table. Manual operation of the test receiver is Almost any number of channel tables completely integrated into the simple can be saved on or recalled from a VSA menu system. Operation of the test diskette or the built-in harddisk. All receiver is very comfortable thanks to the functions of manual operation can its three pop-up menus. also be remote-controlled.

The required receive channel is set in With the test receiver integrated into the Set RF Channel/Freq menu (FIG 3). Video Measurement System VSA, a This can be done by selecting a chan- complete TV measuring and monitoring

FIG 2 Measurement of modulation-dependent nel or program number from the stored system including all receive, analysis, phase modulation of vision carrier channel table or by direct entry of the control and logging functions can for receive frequency. A continuous, auto- the first time be implemented in a single matic frequency search with settable compact unit (FIG 4). The excellent re- threshold is provided for detecting ceive performance data together with unknown transmitters. If only the trans- the versatile measurement functions mitters of the stored channel table are make VSA the ideal all-in system for TV- to be considered, fast channel search transmitter and CATV applications. can be used. For practical use it is of Richard Finkenzeller; Ernst Polz great advantage to set the receive channel with the monitor picture displayed. If the monitor picture is suitably set in the background, the measurement data of the scrolled receive channels can be read direct without any

FIG 3 Display with RF parameters and control switchover between menus. The pa- Reader service card 150/16 for further infor- menu of test receiver rameters of the test receiver, eg volume, mation on VSA

News from Rohde & Schwarz Number 150 (1996/I) 45 Application notes

Radiocommunication system helps Italian customs authorities in coastal monitoring

FIG 1 Patrol boat of customs authorities and The main components of the commu- ticipating units monitoring a specific communication system from Rohde & Schwarz nication system are an external area of the sea. Every PU can assume radio system (HF and VHF/UHF), inter- the function of the NCS. To keep the nal communication unit, central control time required for a complete network and message-handling system. 400-W cycle to a minimum, the total number Transceiver XK855 with integrated of participating units should not be FSK modem, ALIS processor [1] and more than 15. With a length of more than 5000 km, fast HF modem is used as the HF in part difficult to access, rocky and transmit/receive station. The VHF/UHF Error-free, interference-resistant trans- jagged, the coastline around Italy is radio system consists of Transceiver mission of radar data and short opera- anything but simple to monitor and XT452 with external 2.4-kbit data tive messages is at the top of priorities. control. Italian customs authorities have modem and two VHF units provided Transmission of messages according the task of monitoring their coastline by the user. The approved and tested to ACP127 comes next in importance. borders with different classes of patrol DICS (Digital Internal Communications Three types of data link are available: boats (FIG 1) to prevent smuggling System) serves for internal communi- • VHF RSX.25 data link (RSX.25 = and illegal immigration. With the radar cation. The core of the radio system R&S adaptation of wired X.25 pro- equipment used it is possible to monitor is the MERLIN system processor [2]. tocol to the HF radio channel), vessel movements and individual ob- It controls the radio equipment, sets • HF RSX.25 data link, jects at close range. With a large num- the DICS, acts as the link between • HF ALIS long-range data link. ber of rapidly moving objects, how- the radar and the position controller, ever, patrol boats soon reach their generates and processes messages The red circles in FIG 2 indicate the limits. The Tactical Data Link System and also controls data flow. radar range of the individual PUs. developed by Rohde & Schwarz is a The dark green circle around the NCS real help in such a situation. The radar The operative and communicative defines the communication area displays of the patrol boats are collect- procedure is as follows: covered by VHF (line of sight). The ed in a control center and the overall Several patrol boats form a task light green circle represents the area long-range radar display derived from group which is interconnected by a covered by HF. Operations in the two the individual displays is then sent star-shaped radio network on HF and circles take place simultaneously. All back to the boats. A message-handling VHF (FIG 2). The Net Control Ship PUs of the VHF circle also participate system integrated into the transmission (NCS) is the network manager, which in the HF circle. If a PU exceeds link transmits messages to the single controls data exchange with the other the VHF range of the NCS, data boats, coordinates their actions and participating units (PUs). As a rule, a exchange is automatically performed allows efficient action to be taken. task group consists of about five par- in the HF circle.

46 News from Rohde & Schwarz Number 150 (1996/I) Application notes

In a polling method the NCS queries tance. The ALIS processor allows auto- 4th step (ALIS login/logout); applies the radar information of the individual matic link setup, automatic frequency if the number of participants in long- PUs and then retransmits the overall change with adaptive reaction in case range ALIS mode is changed. NCS radar display to the PUs. While of channel disturbances and restores 5th step (ALIS Association Group); data exchange between the units is the connection if a PU is no longer in the data (radar and messages) are usually transmitted by means of an contact. transmitted to other NCS, the regional RSX.25 data protocol at both HF and control center and to the Rome head- VHF/UHF, the frequencies from PU to The communication procedure can quarters in long-range ALIS mode. PU can be quite different. Moreover, be explained by way of the HF super 6th step (ALIS passive free slot); this data are protected using an FEC cycle. Apart from the long-range ALIS step serves for the registration of new method and transmitted in packages mode, the structure of the VHF super PUs. according to RSX.25 at 2.7 kbit/s. cycle is identical with the HF super After the completion of a cycle, all the cycle. A later stage will also allow the trans- boats of a task group have the overall 1st step (login/logout of PUs); mainly mission of video or infrared stills so position display. If an object to be performed if there is a change in the that the PUs pursuing a suspect vessel monitored is in the detection range of number of network participating units. have photographic proof to intercept the PU which is farthest offshore and if 2nd step (single poll); exchange of the right target. The video cameras on this object moves rapidly towards the radar data in RSX.25 mode with all PUs the patrol boats will be networked coast, it can be intercepted by the PUs (top priority). This radar cycle to all PUs with the MERLIN system processor. cruising near the coastline. The actions is run several times. The number of The digitized and compressed stills to be taken are coordinated by the polling sequences is fixed in the con- (approx. 40 to 80 kbit) according to NCS and passed on by the message- figuration setup of the NCS operator. the required resolution will be pro- handling system. Data exchange Error-free data transfer is guaranteed cessed as a file in the message- (radar and messages) with other NCS, thanks to FEC protection, the RSX.25 handling system. Helicopters and air- the coastal stations and headquarters protocol with 2.7-kbit burst transmis- planes can also be equipped with the in Rome is usually managed in ALIS sion and multiple transmissions. data-link method. These “flying PUs” long-range mode because of the dis- 3rd step (RSX.25 Association Group); will close the gaps between the differ- transmission of message-handling data ent task groups, extend the radar range in RSX.25 mode (2nd priority). and allow more long-range actions. Manfred Jungherz; Peter Maurer

FIG 2 Communication scenario

Rome headquarters

Coastal station

REFERENCES [1] Greiner, G.: Reliable shortwave with ALIS. News from Rohde & Schwarz (1988) No. 116, pp 47– 50 [2] Maurer, P.; Völker, K.: Multimedia communication with MERLIN system processor. News from Rohde & Schwarz (1993) No. 142, pp 27– 28

Reader service card 150/17

News from Rohde & Schwarz Number 150 (1996/I) 47 Refresher topic

Digital modulation and mobile radio (I)

When speech is transmitted using digital mobile radio, it is first of all digitized and then source- and channel-coded. On the one hand, this ensures that the data stream from the source coders has a considerably lower bit rate than the original data signal and, on the other, channel coding provides additional error control for transmissions via the radio channel. The channel-coded data stream is a sequence of bursts which are transmitted using a combined FDM/TDM method. The modulation techniques used must be tailored to the radio channel. Our new refresher topic describes how the information to be transmitted is modulated onto an RF carrier and recovered in the receiver with special reference to GSM networks. example Tbit/2, and goes to 0 for Due to the nature of the topic, the fundamental relationships will be expressed the rest of the time. Either signal can be mathematically using complex numbers where necessary. unipolar or bipolar. If they are unipolar, one of the two logical symbols is repre- Rohde & Schwarz has special expertise in the field of digital mobile radio. We are sented by a finite (positive or negative) involved in an extensive range of activities from consultation on various technical voltage, the other by 0 V. Bipolar sig- committees, in particular the earlier Groupe Spécial Mobile, which gave its name nals represent the two logical symbols to the European GSM network, through the development of a complete range of by voltages with opposite polarities. test equipment and systems to the provision of a wide range of system simulators. Rohde & Schwarz also organizes training courses ranging from the practical to The sequence a(n) is mapped digitally the theoretical which are specially tailored to the needs of network operators and onto the baseband signals. First of system users. This was the starting point for this refresher topic. all, the sequence a(n) is replaced by a sequence of weighted Dirac delta functions a(n) · δ(nT) ε {0;1}. To produce a unipolar NRZ signal, this 1 Modulating signals and sequence is fed into an interpolation tively. These signals do not necessarily filter with the transfer function: RF carriers have to remain constant over the dura- sin π f T Initially the information to be trans- tion of a bit. This means that digital H(f) = ———— = si(π f T) (1a) π f T mitted is in the form of a sequence a(n) modulation is simply the process of comprising elements from the set selecting one of the M = 2k possible or with the impulse response a ε {0; 1}. The modulator converts this baseband or RF signals and assigning 1 T T – for – ––––bit ≤ t ≤ ––––bit sequence of logical ones and zeros this signal to a block of k bits. This pro- T 2 2 h(t) =ͭ (sin x/x lowpass filter) into a sequence of analog signals cedure is referred to as M-ary modula- which are suitable for transmission. tion (FIG 1). 0 elsewhere (1b) The conversion of this sequence into voltages in the baseband is referred 1.1 Baseband modulation To generate a bipolar signal, –0.5 is to as baseband modulation and the added before filtering and the sum sig- conversion of these baseband signals An NRZ signal (non return to zero) is nal [(a(n) –0.5) · δ(nT)] ε {–0.5; +0.5} into RF signals is termed RF carrier mod- a signal that remains at a constant, is multiplied by 2. D/A conversion ulation. In general a block of k bits from non-zero value over the duration of a (FIG 2) is then performed after digital the sequence a(n) can be represented bit Tbit. The opposite is an RZ signal filtering. However, the NRZ signals by one of the M = 2k possible states (return to zero) which only has a non- generated in this way are not band- of the baseband signal. For example zero value for a fraction of Tbit, for limited and, theoretically, would give a “block” comprising one bit can be rise to an infinitely wide RF spectrum represented by one of two voltages, 0 after carrier modulation. The sin x/x or 5 V, or by one of two RF frequencies, lowpass filter is, therefore, replaced by f + ∆f or f – ∆f. A block comprising a lowpass that provides more effective two bits (a dibit) can be represented by bandlimiting (eg with a cos rolloff or one of four voltages or by one of four Gaussian transfer function). After D/A Modulator with frequencies and so on. The states of the 16 RF output conversion the sampling frequency signals baseband signal and the RF signal can from the digital section still has to be re- be expressed in an even more general moved from the modulating signal by form as signals ui(t) and si(t) respec- FIG 1 M-ary modulation (here M = 16) means of an analog lowpass.

48 News from Rohde & Schwarz Number 150 (1996/I) Refresher topic

pressed carrier. The modulating signals are functions such as cos[ϕ(t)] and Output signal of ϕ sin x/x lowpass filter –sin[ (t)] for example.

Over- Digital sampling filter To determine the degree to which the signal is distorted as it passes through FIG 2 the communication channel, all that Output signal of Generating needs to be known is how the commu- lowpass with Nyquist edge baseband signals nication channel affects the envelope of these two components. Introducing 1.2 Description of RF signal ϕ π sI(t) = A(t) · cos[ (t)] · cos(2 fct) the complex envelope of the complex The expression and signal: ϕ π jϕ(t) j2πf t sQ(t) = A(t) · sin[ (t)] · [–sin(2 fct)] (3) s(t) = A · e · e c , (4) √—————l π ϕ s(t) = 2Ebit/Tbit · a(t) · cos[2 fc(t)t+ (t)] with which is related to the real RF signal by (2) π ϕ jϕ(t) j2πf t s(t) = A(t) · cos[2 fct + (t)] = sI(t) + sQ(t). s(t) = Re[A · e · e c ] (5) represents the RF signal as a real func- is a good way of doing this. tion, where Ebit is the energy transmit- This type of representation, which is √————l ted per bit. Consequently 2Ebit/Tbit is of course also valid for unmodulated The complex envelope, which is also re- the voltage drop across a 1- Ω resistor. RF signals, makes it a lot easier to ferred to as the equivalent baseband The term a(t) gives the amplitude as understand modulator operation. signal, then has the form: a function of time, fc(t) the carrier fre- ϕ √————–— l jϕ(t) quency as a function of time and (t) The amplitudes of the two modulated u(t) = 2Ebit/Tbit · e the instantaneous phase. To simplify the I/Q components are functions of time = A · cos[ϕ(t)] + jA · sin[ϕ(t)]. (6) √————l notation, the expression 2Ebit/Tbit · a(t) even when A(t) = A = const. or a(t) = 1, is often replaced by A(t) or, if a(t) is in other words even when the RF signal The similarity between the complex constant, by A; s(t) is also referred to has a constant envelope as is the envelopes and the I/Q representation as the bandpass signal provided its case for networks using modulation of the real signal is striking. bandwidth is small in comparison with techniques based on the GSM stan- the carrier frequency fc. dard (GSM stands for Groupe Spécial Mobile or Global System for Mobile The RF signal can also be described Communications). They can also be in terms of its I and Q components (in- thought of as double-sideband am- phase and quadrature). They are: plitude-modulated RF signals with sup- To be continued. Peter Hatzold

Feedback

Mail from South Africa

Hugo Schmitt of Faure in South Africa who collects old radio equipment, receivers and valves sent us the opposite photograph. He writes: “I enclose a picture of some old Rohde & Schwarz equipment which I am sure you will recognize. The VHF relay receiver (editor: front middle, type ESB, market launch 1951) was taken out of service by the South African Broadcasting Company, as they are converting to stereo transistor equipment. These old sets (I have three) have been in continuous use for 30 years and still work perfectly!”.

News from Rohde & Schwarz Number 150 (1996/I) 49 Software

Software SME-K1 for programming the data generator of Signal Generator SME

The strong points of SME come into Programming on a PC is greatly facili- ease of operation. The Fill function, for play especially when RF signals with tated by Software SME-K1. It allows example, allows a predefined area different types of digital modulation are convenient generation and compilation to be overwritten with a user-defined to be generated [1]. SME is capable of data sequences for a wide variety pattern of up to eight bits or with a of GMSK, π/4-DQPSK, GFSK, FSK, of tasks. The software is organized in pseudo-random bit sequence (PRBS), 4FSK and FFSK modulation and is thus three menus (file, edit, transfer) and which repeats after 127, 511, 2047, suitable for testing practically any type offers functions for file handling, editing 32,735 or 65,535 bits (FIG 1). A spe-

FIG 1 Window with Fill editing function FIG 2 Display of standard signal sequences supplied with SME-K1

of mobile-radio network. Pseudo-ran- and transfer of data from and to SME. cial function – Continuous Use of PRBS dom bit sequences or user-specific The software can be operated via a – makes it possible to insert defined data can be used as modulation data. keyboard or mouse. Hotkeys are pro- bit sequences into the PRBS without To store the data in SME, the DM coder vided for fast activation of the main the sequence being started from the option with 8192-bit memory depth is functions. beginning. GSM bit-error-rate meas- available [2; 3]. When the DM memo- urements, for example, require long ry extension option is used in addition, Here are details of the three menus: PRBS sequences, whose contents are storage capacity is increased to nearly distributed to many consecutive time 8 Mbits (precisely 8,388,480 bits). The file handling menu contains all slots. Apart from the PRBS data, each functions required for the generation time slot must contain tail bits and In addition to the modulation data, of new data sequences, their storage training sequences. The Continuous information on the level attenuation in and call from the PC. The PC offers Use of PRBS function allows the PRBS to required in some mobile-radio net- virtually unlimited memory capacity for be continued with no break after these works and on the burst mode is stored. a diverse variety of data sequences. synchronization bits have been entered. While the SME operating menu in- With the Insert, Append and Delete cludes an editor for entering data into The editing functions are structured in functions, the length of the data se- the DM coder, it is in most cases more three areas (Data, Level Att and Burst) quence can be varied subsequently. convenient to use a PC, which is the that can be edited separately. Data Insert, Append and Delete act on each only viable alternative for handling are entered by overwriting the default of the three data areas, so that Data, the masses of data generated by the values with 0 or 1. Various additional Level Att and Burst always have the memory extension option. functions are provided for enhanced same length. The Rotate function makes

50 News from Rohde & Schwarz Number 150 (1996/I) Software

it possible to adapt the burst data to interface (PAT-B1 or compatible) must different signal delays in SME. be provided and driver GPIB.COM installed. The transfer menu contains the Trans- Albert Winter fer and Receive functions. The Transfer function starts data transfer to SME. The

Receive function loads data from SME REFERENCES to the PC. It is thus possible to save the [1] Lüttich, F.; Klier, J.: Signal Generator SME – entire data contents of SME if new data The specialist for digital communications. are to be stored in SME temporarily. News from Rohde & Schwarz (1993) No. 141, pp 4 –7 FIG 3 PC with Software SME-K1 and Signal Standard signal sequences for the Generator SME [2] Application Note 1GPAN08: SME with option DM coder, hints for using the data most important communication systems, generator eg GSM, DECT, ADC and PDC, are [3] Application Note 1GPAN14: Simulation of supplied with the software (FIG 2). BCCH channel of GSM/PCN base station demands on the PC. SME-K1 requires with Signal Generator SME Hardware requirements: Software no more than 450 Kbytes of RAM. SME-K1 runs under the MS-DOS oper- Since data transfer to SME is via the ating system and makes very little IEC/IEEE bus (FIG 3), an IEC/IEEE-bus Reader service card 150/18

Calibration method for network analyzers Patent

The TOM-X* calibration method is a further ideal characteristics of the system and describes measurements possible – even at signal levels development of the TOM calibration technique. all possible cross couplings. The scattering ma- lower than system crosstalk. This feature is Unlike conventional calibration methods, trix of the error fourport has 4 x 4 = 16 complex particularly useful for on-wafer measurements TOM-X is based upon a mathematically exact elements, one of which can be eliminated where crosstalk of about 40 dB may arise model that describes all possible cross by normalization. The remaining 15 unknown between the test probes. couplings between the four receive channels. terms have to be determined for each frequency As a consequence, this method allows these point by vector calibration measurements. cross couplings to be eliminated analytically. German patent DE 43 32 273 A1 The error model shown in the figure below is The TOM-X calibration method is highly effec- Date of application by Rohde & Schwarz used as a basis (full model). An error fourport tive, but is extremely involved. Unlike other cal- 23 September 1993 is inserted between the DUT and the twoport ibration methods, two oneport standards have Date of publication 16 June 1994 network analyzer, eg ZVR. It represents the non- to be connected simultaneously to the two test Inventors: ports of the network analyzer. The term “double Prof. Dr.-Ing. Burkhard Schiek; oneport standards” is therefore often used in Holger Heuermann this context. A total of five twoport calibration DUT measurements are required: direct through- connection of the two test ports, matched load at both ports, matched load at port 1 and simultaneous open-circuit of port 2, both test ports open-circuited, and port 1 open-circuited with simultaneous matched load at port 2. Error fourport After calibration the system-error correction

Ideal network analyzer facility calculates a mathematically exact correction that eliminates crosstalk in a highly effective way and so increases the overall dynamic Used in vector network analyzers range of the system. TOM-X is the only twoport * Heuermann, H.; Prof. Dr.-Ing. Schiek, B.: Results of from ZVR family Network Analyzer Measurements with Leakage Errors calibration method which is able to correct DUT- Corrected with the TMS-15-Term Procedure. IEEE MTT-S dependent crosstalk. This is why it is called Reader service card 150/01 International Microwave Symposium, San Diego (1994) TOM-X, X referring to crosstalk. The reduction for further information on ZVR pp 1361–1364 of crosstalk achieved by TOM-X makes exact

News from Rohde & Schwarz Number 150 (1996/I) 51 Panorama

Remarks on the future of radiocommunications

On the occasion of the 100th anniversary of radiocommunications, Rohde & example, the cordless phone is on its Schwarz invited many guests to celebrate this event in Munich (see also our way to becoming an inexpensive con- Newsgram on page 58 in this issue). Hans Wagner, President and COO of sumer article worldwide. This was not Rohde & Schwarz gave an outlook on the second century of radiocommunications made possible by digitization alone. (FIG). Here is an extract from his speech. This follows straight on from the edito- It was only by microprocessor tech- rial in NEWS 149, describing the contribution of Rohde & Schwarz to the history nology that the dream of high-perform- of radiocommunications until the present day. ance consumer articles came true. Many hundreds of thousands of transistor functions are united on just a The future of radiocommunications, in few square millimeters. A precondition particular the future of terrestrial radio, for units to become favourably priced appeared to be without any great is the production of large quantities. prospects in the eighties. Apart from This is only possible by worldwide classic mobile applications (such as in standardization of the basic systems. cars, airplanes and ships) which could For GSM this approach was successful. not be mastered otherwise, the future For DAB and DVB it is likely to succeed. seemed to belong to the optical fiber beside the copper cable. But then a There are thus two technological driv- development was initiated, starting ing forces – ie digitization with coding out from data technology and data and high integration of the products transmission, which introduced revo- to be implemented – that have offered lutionary changes for all other fields of and will continue to offer new prospects Hans Wagner, President and COO of Rohde & information technology and commu- Schwarz, made the final speech when the 100th to radiocommunications. The most im- nications: the linking together of infor- anniversary of radiocommunications was cele- portant impetus, however, is the liber- mation processing and transmission by brated at Rohde & Schwarz alization and deregulation that have means of optimized and standardized been initiated worldwide. It was only coding methods. It was known that the through competition (now also in the transmission channel could only be field of radiotelephony) that the num- used optimally if the digital or – if only ber of subscribers sharply increased available in analog form first – digi- phone and the wireless cable or wire- because of interesting new services as tized information were prepared be- less local loop. well as falling charges and that the use forehand to allow optimum matching of integrated circuits led to favourable to the transmission channel. Suddenly At the same time development of prices. After mobile radio, this compe- solutions became feasible that could redundancy-reducing methods in par- tition is going for broadcasting and will only be dreamt of over the years: prac- ticular for vision and sound transmis- change it. Just think of interactive serv- tically error-free, undisturbed transmission is surging ahead. Methods making ices. Multimedia services which are sion of information was possible via the use of human physiological, acoustical now implementable first have to be sep- most difficult and susceptible channel, and optical perception (key word arated from one another and allocated namely the radio link with all its disturb- MUSICAM for sound broadcasting) to generic terms such as broadcasting ing effects. coupled with modern multi-carrier or individual communication. modulation have paved the way to It was with digital technology that digital audio broadcasting (DAB) and The use of wireless communication via mobile radio was to be tackled, all digital video broadcasting (DVB), electromagnetic waves will be more available techniques such as source which are becoming of interest world- and more versatile in future. Digital coding, time multiplexing, band wide and are already in use in pilot technology made radio an equal spreading being made use of. Ultra- networks (see articles on page 58). partner with optical fiber and copper modern modulation methods were cable for a variety of applications. employed and the standard (GSM) With the exception of broadcasting, Radio systems except those with high that was quickly accepted worldwide radio used to be the technology for transmitting power in the kW range was born. Development which first authorities and for amateur operators. or higher are physically mobile and was started with the mobile phone Even the costly analog carphone was quickly set up. That is why they are now continues with the cordless digital a privilege for only a few. Today, for preferred to wire and glass.

52 News from Rohde & Schwarz Number 150 (1996/I) Panorama

Due to the future and practically ex- organizations will more than ever shifted towards commercial and public clusive use of digital transmission with- before be required to deal with the use according to the law of supply and in the field of radiocommunications, problems of avoiding or eliminating demand. technical developments will, even more mutual interference and of supporting strongly than today, concentrate on the desired competition of the network As almost unlimited, complex appli- software and especially coding and and service providers as best as pos- cations are possible in the radio signalling. The generation of high RF sible. The impelling use of highly inte- channel thanks to digital technology, power will become more and more grated circuits in the radio equipment radiocommunications will in many unimportant compared to intelligent, of the future calls for stable, reliable cases become an integral part of adaptive methods of managing trans- and close cooperation with chip manu- hybrid systems. All this calls for real mission power, as already used with facturers and for access to software international cooperation within in- GSM, or compared to methods and required for modelling, simulation and dustry, among network operators and concepts that use low transmission testing of equipment. service providers but also between power in the first place. As a result each of the three groups in order to of the fast growing use of radio tech- In the long run only radio applications be at the front with the competitors. nology, electromagnetic compatibility based on internationally used stan- On the threshold of the second cen- and its optimization will become more dards and methods will survive. Any tury of radiocommunications Rohde & and more important, especially in constraints in the use of radiocommuni- Schwarz has attuned to the situation those applications reserved for wire cations will exclusively lie in the limited and will face the challenges of future and optical fiber (eg last mile, wireless resource frequency including its physi- radio systems and international part- LAN or local loop). cal limitations as far as propagation nerships with all its energy. and compatibility are concerned. Hans Wagner In this case also the national frequency Apart from a few exceptions (security, allocation and frequency management military) frequency allocation will be

Multimode Radiocommunication Tester CMD for GSM, PCN, PCS and DECT mobiles

With its CMD family, Rohde & Schwarz provides testers for mobiles used in all internationally significant types of digital, cellular mobile-radio networks. FIG 1 All the units have the same look and a Multimode radio- similar design. Differences only occur communication tester CMD for mobiles when certain test facilities and operat- to GSM, PCN, PCS ing procedures have to be optimized and DECT standards for a specific network. Photo 42 198

A single CMD (FIG 1) now encom- tion and service measurements – in maximum flexibility and adaptability passes both GSM/PCN/PCS and particular for the dual-mode mobiles to future requirements. Upgrading is DECT test technologies and so even of the future. The desired additional no longer a problem and units that more benefit can be derived from measurement functions are provided are already in use can be converted synergies and standardized produc- by means of options which ensure at minimum cost.

News from Rohde & Schwarz Number 150 (1996/I) 53 Panorama

The option concept and the signalling units for both GSM/PCN/PCS and DECT have major advantages for dual- Basic modules Basic modules mode mobiles in particular as these mo- GSM/PCN/PCS biles support DECT and GSM or similar GSM/PCN/PCS DECT extension DECT modules modules extension standards. The signalling units are optimized to obtain the best measurement speed for the network in question. As there are two signalling units, there is no need to load different operating FIG 2 Concept of multimode facility for Digital software for different systems and this Radiocommunication Tester CMD maintains high measurement quality, ease of measurement and speeds up the process. This is highly measurement speed with separate functional advantageous in manufacturing envi- units including signalling. ronments because speeding up a test procedure by even a few seconds may make the difference between mobile as manual and remote control together REFERENCES production being economical or not. with the high measurement speed [1] Mittermaier, W.; Holzmann, G.: Digital remain exactly the same. Radiocommunication Tester CMD55 – GSM and PCN tester in one compact unit. News CMD52 for GSM, CMD55 for Michael Vohrer from Rohde & Schwarz (1994) No. 145, GSM/PCN/PCS [1; 2] and DECT pp 18 –20 Tester CMD60 [3] can be converted [2] Vohrer, M.: Advanced test technology into a multimode radiocommunication for GSM/PCN mobile phones with tester (TABLE). CMD55 with DECT CMD52/55. News from Rohde & Schwarz GSM PCN PCS DECT (1994) No. 145, pp 48 –49 option, for example, is nothing other (DCS1800) (DCS1900) than a combination of CMD55 and [3] Maucksch, T.: Digital Radiocommunication CMD52 • o o o Tester CMD60 – A favourably priced com- CMD60 (FIG 2). Implementing multi- CMD55 • • o o pact test set for series production of DECT mode capability by combining two CMD60 o o o • mobiles. News from Rohde & Schwarz units does not involve any trade-offs. (1995) No. 149, pp 13 –15 TABLE: CMD models for GSM, PCN, PCS and Every single measurement facility, the DECT with multimode options (• = as standard, excellent data of the basic units as well o = optional) Reader service card 150/19

Low-cost Service Radiocommunication Testers CMD50/53 for GSM/PCN/PCS mobiles

The digital radiocommunication testers service applications and attractively has an RS-232-C remote interface of the CMD family for GSM, PCN priced, to the family: CMD50 for instead of a high-speed IEC/IEEE-bus (DCS1800) and PCS (DCS1900) have GSM and CMD53 for GSM, PCN and interface. The multifunction connector gained remarkable market acceptance optionally PCS (FIG). for accessing the I/Q signals of the thanks to their universality, high meas- internal CMD modulators and demod- urement accuracy and high measure- The new models are based on their ulators, which are only of relevance ment speed and are used by almost counterparts CMD52 and CMD55 for production and development, is every manufacturer of mobile phones. [1 to 3] but are stripped of those test solely for CMD52/55. The high-level Rohde & Schwarz has now added facilities that are not relevant to serv- RF output on CMD52/55 as well as another two members, both ideal for ice applications. Thus CMD50/53 the RF input/output and highly sensi-

54 News from Rohde & Schwarz Number 150 (1996/I) Panorama

tive second RF input for special module grams, eg for production, can also cost-effective solution for service appli- production tests are available as be used for service testing. The blue cations but can also enjoy the advan- options for CMD50/53. This ensures box gives a clear overview of all the tages of the coherent test philosophy that testing mobiles of the future which available options and accessories for that provides almost identical test tech- may have an integrated antenna and Digital Radiocommunication Tester nology from module testing and final no RF connector will not be a problem. CMD50/53. production testing with CMD52/55 A DC ammeter/voltmeter with GSM- through to maintenance and service specific test curve is also available as With CMD50/53 a manufacturer of with CMD50/53. an option. mobiles not only has an attractive, Michael Vohrer

GSM, PCN and PCS mobile Radiocommunica- REFERENCES Options tion Tester CMD53 for service and maintenance CMD-B1 OCXO Reference Oscillator [1] Mittermaier, W.; Holzmann, G.: Digital Ra- at a favourable price Photo 42 288 CMD-B3 Multi-Reference Frequency diocommunication Tester CMD55 – GSM Inputs/Outputs and PCN tester in one compact unit. News CMD-B4 Phase/Frequency Error, from Rohde & Schwarz (1994) No. 145, Power Ramping and pp 18 –20 BER Measurement CMD-B41 AF Measurement Unit with [2] Vohrer, M.: Advanced test technology Frequency Counter for GSM/PCN mobile phones with CMD-B42 Power Ramping Measurement CMD52/55. News from Rohde & Schwarz with High Dynamic Range (1994) No. 145, pp 48 –49 CMD-B43 GSM-Spectrum [3] Mittermaier, W.: Module test with Digital Measurements Radiocommunication Tester CMD52/55. All other facilities, technical data and CMD-B62 Memory Card Interface (CMD-B6 also required) News from Rohde & Schwarz (1995) operation are identical for the four CMD-B19 PCS Extension (for CMD53) No. 149, pp 36 –37 units. As a result, joint operation and CMD-B20 DC Ammeter/Voltmeter replacement are straightforward and, CMD-B30 High-Level RF Output, Sensitive RF Input if CMD52/55 is used for production Accessories testing and CMD50/53 for service CMD-Z1 Formatted Memory Card work, one can be absolutely certain CTD-Z10 Antenna Coupler with Shielded Chamber that the instruments’ responses are iden- Software tical and results are 100% consistent. CMD-K43 Narrowband Spectrum Analysis Automatic, internal sequencing pro- Reader service card 150/20

News from Rohde & Schwarz Number 150 (1996/I) 55 Panorama

CMD compact tester R4860 tests telephones of Japanese mobile-radio network PDC

Manual operation of the tester is supported by a large high-contrast LCD display, softkeys and user prompts. No prior knowledge of PDC is required to operate the unit. The parameters are preset to standard values in the configuration menu just like the pass/fail limits. Thus the test routine for the mobile station is very easy and simple to perform. A useful contribution in this regard is the automatic display of key results. This ease of operation is a great help when equipment is being serviced.

All the single tests and test results are also available at the remote interface (IEEE 488). High measurement speed, especially via the IEC/IEEE bus, pre- destine R4860 for final testing on the Digital Radiocommunication Tester R4860, com- Production and service tests on mobiles production line. pact tester based on CMD units, for transmitter are essential for picking up manufactur- Thomas Maucksch and receiver tests on mobile phones of Japanese network PDC Photo 42 333/1 ing faults and detecting defects caused by wear and tear during operation. These defects are mainly detected by Together with its Japanese partner testing the RF interface. The signalling Advantest, Rohde & Schwarz, a world software in the mobile station is not leader in test technology for mobile involved. Via a control interface, the radio, has developed a tester for the radiocommunication tester sets the Japanese digital mobile-radio network mobile phone to a state in which the PDC (personal digital cellular). Digital tests can be performed. Radiocommunication Tester R4860 (FIG) is based on the successful CMD Transmitter tests in R4860: family (see pages 53 and 54 in this a) frequency accuracy of carrier, issue). Mobile phones for the digital b) occupied bandwidth, network currently being introduced c) transmit power, power ramping, in Japan are tested during service, d) leakage power between time slots, maintenance and production. The key e) modulation, parameters of the PDC network are: f) adjacent-channel power, spurious emissions, Frequency range g) bit rate error. MS → BS 940 to 956 MHz and 1429 to 1453 MHz Receiver test: BS → MS 810 to 826 MHz and 1477 to 1501 MHz h) sensitivity (BER). Power 4 power stages up to 3 W Tests a, b, c, e, g and h ensure that the Channel spacing 50 kHz (interleaved user has a high-quality communication channel spacing 25 Hz) link; b, d and f ensure that a large num- TDMA 2 out of 6 timeslots, frame length 40 ms ber of subscribers can use the network Modulation π/4-DQPSK without causing mutual interference. Reader service card 150/21

56 News from Rohde & Schwarz Number 150 (1996/I) Panorama

Gas chromatography for monitoring production processes in chemical industry

It is essential to monitor every subpro- For example, the Micro PGC 400 can growing demand for easier operation, cess of a manufacturing process. This analyze 33 refinery gases in less than more user-friendly design, lower oper- is why the composition and quality of three minutes, injection and analysis ating costs and greater flexibility. end and intermediate products also taking place simultaneously on four Thanks to a variety of options – such have to be monitored. High-speed multi-component analyzers are used to ensure that modern production processes are highly efficient. In this respect, minimizing operating costs is just as important as simple and rapid integration into the production environment.

The gas chromatograph is a typical multi-component analyzer. It is able to separate complex gas mixtures and analyze their components. The method makes use of the different solubility of substances in a mobile and a stationary phase. In the stationary phase, the gas mixture is trans- ported through a coated separation column by a carrier gas. Different components take different times to pass along the column and so they become separated. Finally a detector records the time sequence of the gas components.

As part of a new product range, Process gas Rohde & Schwarz Cologne has devel- chromatograph oped a modern process gas chromato- Micro PGC 400 graph (PGC), Micro PGC 400 (FIG), for analyzing for use in tough industrial environ- 33 refinery gases ments. The core of this unit is a miniaturized gas chromatograph whose components are micro-machined from channels. Conventional systems would as a range of injectors, backflushing, silicon. This extremely high-precision take about 20 minutes under the explosion-proof measures, sampling technique has been borrowed from same conditions. The Micro PGC can systems, alarm functions – together micro-chip production. The use of therefore now be used for applications with application planning, Rohde & micro components – such as valves – that were previously unsuitable for Schwarz has a turnkey system which guarantees a long operating life gas chromatographs because they can be tailored to the needs of the and extra short analysis times. The were too slow. customer. use of a miniaturized injector and Dr. Andreas Waßerburger detector makes the Micro PGC 400 Extremely short cycle times and long between ten and 20 times faster operating life are obtained by using than conventional GC systems. The appropriate backflush precut columns separation capability is also excellent to vent with switching. This multi-com- of course. ponent analyzer fully meets industry’s Reader service card 150/22

News from Rohde & Schwarz Number 150 (1996/I) 57 Newsgrams

DAB live in Peking He Dong Cai was very impressed Coinciding with the start of the DAB by the live broadcast from Munich pilot project in Bavaria in October to Peking, thanking everyone in- 1995 (see following report), an volved and announcing the start international broadcasting sym- of a DAB pilot project in southern posium was staged in China with China next year. J. Beckmann focus on DAB (digital audio broadcasting). A Rohde & Schwarz team travelled to Peking to attend the important event. The company’s capa- Start of DAB project in Bavaria bilities in the sector were demon- On the occasion of the media strated through lectures and a live conference in Munich in October broadcast of the DAB program of 1995, the go-ahead was given for Bayerischer Rundfunk (BR) via satel- the world’s biggest DAB network, lite to Peking and onto the Rohde & the pilot project in Bavaria. The Schwarz exhibition stand. Bavarian state center for new media invited some 800 guests to 100 years of radiocommunications The guests were also shown some- On the morning after the official the event on the Praterinsel in Mu- – good reason for R&S to celebrate thing of the major areas in which DAB start, following the early- nich, including German PTT minis- This jubilee (the subject of the title Rohde & Schwarz operates through morning news, the third channel of ter Dr. Wolfgang Bötsch and minis- and editorial in the last issue of practical examples and demonstra- BR broadcast an item on DAB in ter of state Erwin Huber. Rohde & News) was an opportunity for tions of hardware and software. For Chinese and transmitted it to Peking Schwarz, as general contractor for Rohde & Schwarz to put on a big the evening there was an invitation at the same time, where many visi- the engineering of the DAB trans- show to celebrate achievements to to an official reception in Munich’s tors to the Rohde & Schwarz stand mitter stations, played a large part date and look to the future of radio- Residence. Following a tour of the were surprised by the program live in organizing the evening. An R&S communications together with some treasure vault, the antiquary and from Germany in their native lan- aerial photo of the Wendelstein 200 guests from international pol- the gallery of ancestral portraits, guage and CD quality. With the station was the eye-catcher right in itics, telecoms and industry. On Bavaria’s state minister of econom- support of German Telekom there the foyer. The digital signals broad- the evening of 11 October 1995 the ics, Dr. Otto Wiesheu, welcomed the was also a video conference via cast in the Munich region were illus- arriving guests were ushered into guests and expressed his pleasure satellite between Peking and Mu- trated by a laser projection. a large marquee, set up on the at the fact that so many prominent nich (the photo shows the partici- company’s premises in Munich, for persons from all over the world had pants at the German end). The a variety program “The world of followed Rohde & Schwarz’s invita- guests in Peking were He Dong Cai, radiocommunications”. The climax tion to Munich to see technology vice-minister of the ministry of was the appearance of direct from Bavaria. In a concluding radio, film and TV, who sponsored descendants of radio pioneers address, COO Hans Wagner pre- the symposium, Cheng Xiaoning, Popov and Marconi: Nadejda sented his thoughts on the – digital president of the academy of broad- Mishkinis from Moscow and Capt. – future of radiocommunications as casting science, and Wu Yingjian Vittorio Marconi from Colombia a partner of equal rank to copper of the state science and technology (shown in the photo between R&S cable and optical fiber (extract on commission. In Munich minister of executives Friedrich Schwarz and page 52 in this issue). All this tech- state Erwin Huber, in his welcoming Hans Wagner). nology was rounded off by a cosy address to the Chinese vice-minis- Bavarian evening in the alps to ter, looked forward to the intro- Next day Friedrich Schwarz opened the accompaniment of traditional duction of DAB in China too with the event by welcoming the guests. music. HW/ro the support of Bavarian industry. He underscored the special role of the private and independent concern Rohde & Schwarz on the market and the way it had adapted The official start was then triggered to the new challenges of a digit- by minister of state Huber at the al world. Gerhard O. Pfeffermann, push of a button during a live state secretary from the German relay from the Praterinsel into PTT ministry, outlined in his address the “Bayern-Rundschau” news, fol- the worldwide opportunities and lowing which a special program consequences of telecommunica- “Brisant” was broadcast from the tions deregulation and liberaliza- event by Bayerischer Rundfunk tion. Director Theodor Irmer brought (BR). This included various features words of greeting from the Inter- on the subject of DAB plus international Telecommunications Union views with ministers Bötsch and (ITU) and praised Rohde & Huber, the director of BR, Prof. Dr. Schwarz’s commitment to the radio- Albert Scharf, and the president of communications sector. Prof. Les W. the Bavarian state center for new Barclay and the former director of media, Prof. Dr. Wolf-Dieter Ring. ITU Radiocommunications, Richard C. Kirby, reviewed the milestones in To the applause of the guests, the hundred-year history of radio- Rohde & Schwarz presented a DAB communications with the assistance birthday cake to mark the end of of impressive, original recordings the official part. The 250-kilo work and documents. of art (measuring 1.4 x 1.2 m) was

58 News from Rohde & Schwarz Number 150 (1996/I) Newsgrams

shaped like a map of Bavaria. Coloured icing marked the propagation areas of the digital broadcast signals, and the transmitter stations were modelled in choco- late. Rohde & Schwarz COO Hans Wagner presented the knife to ministers Bötsch and Huber for cutting the cake (in the photo from left: minister of state Erwin Huber, Hans Wagner and Prof. Dr. Wolf-Dieter Ring). The cake went down well, so well in fact that there was nothing left of it. N. Julien exactly to the special needs of the “hunger” of the anaerobic biomass Oregon – designed this, the world’s army. Here, for the first time, a CMS for the effluent components to be first compact CDMA test set, in less was fitted with an RF millivoltmeter. detoxicated is made use of (photo). than 18 months on the basis of the Strict requirements for operating The operating costs and the effort CMD family. M. Scholla Radiocommunication testers CMS environment had to be satisfied, that goes into occupational safety for Australian army and at the same time the range of are small because, in contrast to The Australian army has ordered transmitter and receiver tests was conventional methods, hardly any 154 Radiocommunication Service expanded. G. Higgs extra detoxicating chemicals are Monitors CMS53 from Rohde & needed. And, last but not least, the ENDIEL 95 in Lisbon Schwarz (Australia) Pty Ltd. The enriched precious metals can be re- ENDIEL 95, Portugal’s biggest in- photo shows in the foreground covered from the perished biomass. dustrial show with some 200 ex- brigadier Grahame Hellyer, AM, R. Frodl hibitors, held the stage for five days general director of materials, and Microelectronics at R&S – in the capital Lisbon in the summer of Andrew Bean, managing director showing the way in environment- last year. As part of the show there of Rohde & Schwarz in Australia, at friendly fabrication was also a European EMC seminar, the signing of the contract. These The microelectronics center of supported and organized by ICP test sets will replace a large number competence in Munich produces (Instituto das Comunicacoes de Por- of different instruments currently thinfilm substrates for microwave tugal). This seminar lent ENDIEL 95 used for the repair and mainte- modules. Through continuous follow- international importance. The lecture nance of field-communication and on development of the techniques by Manfred Stecher (EMC expert other electronic equipment in the and technologies, these high-tech at Rohde & Schwarz and member frequency range 1 Hz to 1 GHz. components from Rohde & Schwarz of the CISPR committee) on “Field- CMS53 is practically a complete, are able to satisfy the highest de- strength measurement in the pres- portable multi-purpose mainte- mands. Among the latest examples ence of ambient noise” met with nance workstation that can be of the modern fabrication is the great interest. Together with its Por- powered on DC or AC. development of a layer system qual- tuguese representative Telerus S.A., ified to MIL standard 883, and the CDG forum in Seattle Rohde & Schwarz presented a num- In this contract, which Rohde & introduction of statistical process At the beginning of October 1995 Schwarz won in the face of tough control. Rohde & Schwarz is also the first forum of the CDG (CDMA competition from other well-known exemplary in the treatment of its Development Group), initiated by names in test engineering, the Aus- own waste water, having invested the companies U.S. West and tralian army once more showed its in a new detoxication plant. To- Qualcomm, was staged in Seattle in trust in R&S technology. In the 1980s gether with the manufacturer and the US state Washington. The aim it purchased 300 Signal Generators thanks to the commitment of the of the event, at the foot of the Space SMS and 90 Radiocommunication building department of the city of Needle (photo), was to gain an Testers CMT. Radiocommunication Munich, a fully automatic, biologi- overall view of currently available Service Monitor CMS53 is tailored cal plant was created in which the testing means for CDMA (code-division multiple access) with the aid of leading instrument producers. 250 participants were able to gather information about the capabilities of mapping systems, evaluation ber of new products. In addition to tools, test instruments and systems the very latest in EMC test engineer- through the numerous lectures and ing, examples of modern GSM test demonstrations. The forum was of instrumentation were shown. One special significance for Rohde & exhibit that attracted a lot of atten- Schwarz because it offered an tion was the CTD52, a go/nogo test- opportunity of presenting Digital er for GSM mobile phones. The most Radiocommunication Tester CMD80 prominent visitor to the Rohde & for CDMA to a broad public. Schwarz stand was the Portuguese CMD80 is a joint development minister for industry and energy, Luis between Rohde & Schwarz and Fernando Mira Amaral (second Tektronix (more about the unit in from left in the photo, talking to News 149, p 47). Two teams – one Rodrigo Leitão, managing director in Munich, the other in Beaverton, of Telerus). B. Mohacsy

News from Rohde & Schwarz Number 150 (1996/I) 59 Information in print

Vector Network Analyzers ZVR (for all measure- Microwave Signal Generator SMP (0.01/2 to Listen. Locate. Analyze. This brochure deals with ments and new calibration methods such as 40 GHz); the revised data sheet now also features radiomonitoring and radiolocation and shows TOM-X), ZVRE (for magnitude and phase of all models 03 (27 GHz) and 04 (40 GHz). why Rohde & Schwarz is the ideal partner for s-parameters) and ZVRL (for magnitude and phase Data sheet PD 757.0935.21 enter 150/04 system solutions. of s 11 and s 21) are extremely sensitive and have Info PD 757.1954.21 enter 150/32 a refresh rate of over 25 frames/s; 9 kHz (10 Hz Universal Shielding Chamber CTD-Z10 with An- with option) to 4 GHz, resolution 10 µHz, dynam- tenna Coupler for Mobile Radio (900-MHz band) Encoder Test Sequence DVTS (JPEG, MPEG). This ic range (with option) >130 dB, reference channel for interference-free testing on all cellular net- module contains static and moving picture ele- (ZVR: 2), calibration time <20 s, automatic two- works; attenuation >50 dB. ments for encoder quality assessment. port calibration; numerous options (eg computer Data sheet PD 757.1960.21 enter 150/27 Info PD 757.1790.21 enter 150/33 function). Data sheet PD 757.1802.21 enter 150/01 EMI Software ESxS-K1 for receiver family ESS/ Documentation – mediator between man and ESHS/ESVS is user-friendly and operates under technology. The R & S Cologne Plant guarantees Digital Radiocommunication Tester CMD60 Windows 3.1 (80836 or higher). that its documentation complies with legal pro- (DECT) performs fast RF tests to CTR06 (up- Data sheet PD 757.1848.21 enter 150/28 visions and enhances user safety. gradable for GSM, DCS1800 and DCS1900); Info PD 757.2015.11 enter 150/34 RS-232-C interface, AF tests and IEC/IEEE-bus Sound and TV Broadcasting System STARS (87.5 interface with options. to 108/470 to 860 MHz) for use in inaccessible Data sheet PD 757.1731.21 enter 150/23 areas and under harsh climatic conditions converts New application notes satellite signals to terrestrial frequencies (transmit Digital Radiocommunication Tester CMD80 is a power of 10 W for TV and 20 W for VHF); power Automatic measurements on tape recorders using compact tester for CDMA mobile stations (IS 95) supply 1200 VA. Audio Analyzer UPD including power supplies; RS-232-C interface Data sheet PD 757.1948.21 enter 150/29 Appl 1GPAN19E enter 150/35 (IEC/IEEE bus as option). Data sheet PD 757.1825.21 enter 150/24 VHF-UHF Search Receiver ESMA (20 to IEC/IEEE-bus control of Audio Analyzer UPD 1300 MHz) is the perfect central unit for fast Appl 1GPAN22E enter 150/36 Digital Radiocommunication Test Sets CRTP02, (5 GHz/s) and precise radiomonitoring; high sen- CRTC02; the data sheet now includes CRTC02 sitivity, tracking preselection, large dynamic range, Measurements of dual-tone multifrequency dialling for mobile stations to GSM, DCS1800 and measures frequency offset and short-duration signals with Audio Analyzer UPD DCS1900. signals, optional data analysis, can be powered Appl 1GPAN23E enter 150/37 Data sheet PD 757.0058.22 enter 150/25 both from AC line and battery. Data sheet PD 757.1719.21 enter 150/30 Measurements on tuners using Audio Analyzer EMI Test Receiver ESPC (150 kHz to 1 GHz, UPD and Signal Generator SMT optional range extensions to 9 kHz and 2.05 GHz) Solutions for Coverage Measurements. This bro- Appl 1GPAN24E enter 150/38 for interference weighting to CISPR16-1 (10 Hz chure gives an overview of the coverage measure- PRF) and measurements to commercial EMI ment systems of the TS9950 family for planning, Base-station adjacent timeslot rejection measure- standards; powered from internal (option) or optimization and maintenance of digital radio ment with CMD and SME external battery. networks. Appl 1GPAN26E enter 150/39 Data sheet PD 757.2009.21 enter 150/26 Info PD 757.1925.21 enter 150/31 Schz

Der deutsche Rundfunk Booktalk Faszination einer technischen Entwicklung

by Siegfried Hermann, Wolf Kahle and mention of the achievements of Rohde & Schwarz Joachim Kniestedt. Published 1994 by R. v. in this field. Decker’s Verlag, G. Schenck, Heidelberg. ISBN 3-7685-2394-2, 288 pages, more than Dr. Siegfried Hermann, a scientific assistant in 200 illustrations (six of them from Rohde & broadcasting in East Germany up to the time of Schwarz), available in bookshops, price DM 65 reunification, reports on the development of (only in German). broadcasting there after 1945. Joachim Kniestedt returns to talk of broadcasting in a unified This book was produced in cooperation with Germany and international regulations govern- German Telekom and shows that its predecessor, ing the use of broadcast frequencies. Dr. Wolf the PTT, laid the foundation for the technical Kahle, who long worked for the state broad- development of broadcasting. Joachim Kniestedt, caster in Weimar, for Berliner Rundfunk and familiar as an author of numerous articles on the German PTT, explains the broadcast studio the technology and history of sound and TV engineering of the German PTT. broadcasting, reports on the beginning of broadcasting and its development up to 1989 in The book is interesting for both specialists and West Germany. In the chapter “The ultra-short- those with a general interest in broadcasting. wave for broadcasting – the wave of joy” there is

60 News from Rohde & Schwarz Number 150 (1996/I) Press comments

At the right time Online measurement for the environment Andreas Schümchen of »Medien-Bulletin« spoke in issue 8/95 to Franz Dosch, executive vice The magazine »CHEManager« 9/95 reported president of the sound and TV broadcasting di- on the ENVITEC 95 show: vision at Rohde & Schwarz, about the challenges facing broadcasters: Rohde & Schwarz presented a new online me- tering method for combustion aerosols. Using the DAB is a long due innovation in sound broad- CT-500 immission meter, PAH particles can be casting. It is a European development and invest- detected so that PAH emissions can be traced, lo- ment, and so we are committed to implement it calized and quantified like immissions, and load in Europe… From the source coding in the studio ratios and components can be judged reliably. through satellite up-links and down-links to terrestrial transmitting components, we offer every- thing needed to create a complete, synchronized broadcasting network. On the subject of DBV (digital television): … We have already implemented a pilot project in Switzerland, the combination of a PAL transmitter with a DVB transmitter that broadcasts terrestrially and can be switched by telephone modem to analog PAL or DVB. The Swiss PTT is using this project to investigate Signal Generator SME appeared all of four times coverage quality. All our analog TV transmitters on the cover of » Mercado Electronica« 23/95, are already designed today so that they can go published in Argentina. In the same issue there digital without any modification. was an article by Rohde & Schwarz on the new IEC/IEEE-bus command language SCPI for remotely controlling instruments, making the work of the user very much simpler.

Modern receiver for EMC Quality for the future

In »EMC Journal« 3/95 Wolf Schreyer, product On the subject of ISO 9000 at Rohde & Schwarz, Spectrum Analyzer FSE from Rohde & Schwarz manager for signal analysis and EMC T&M prod- editor Paul Kho interviewed the director of the is used to being a cover star, like on the Dutch ucts at Rohde & Schwarz, gave a summary of the central quality department, Manfred Fleisch- magazine »Elektronica« 9/95. situation shortly before the entering into force of mann, for »Konstruktionspraxis« 8/95: the German EMC act on 1 January 1996, presenting at the same time the concept of Rohde & Rohde & Schwarz got its ISO 9001 certificate in Schwarz’s Precertification Test Receiver ESPC: 1992. That was just the beginning of further im- provement of quality within the company. Not just The development of electronic products is much so that the following audits could be surmounted, too costly nowadays to leave the final result, even but above all for an internal quality policy that in part, to chance. This naturally also applies to will ensure lasting satisfaction of all customers. the interference emitted by such products, which, once the transition period expires on 1 January 1996, will be subject once and for all to the Ger- man EMC act (EMVG) and is due to become a headache for many manufacturers, mainly medium-sized businesses. Now that awareness of the need for such emission measurements has woken from its long sleep, test engineering Multifunctional has adapted to the situation. ESPC sticks out communication among the mass of precompliance receivers, and to emphasize the fact it has been dubbed a The new Accessnet ® digital exchange from R&S precertification test receiver. The risk of unsatis- Bick Mobilfunk was a subject for the communi- factory or even unusable test results is much cations magazine »NET« 8-9/95: smaller, an encouraging factor for those who are not familiar with all the tricks and ruses of Wireless business and administrative communi- interference measurement. cation will now be even more flexible on the Accessnet ® radiocommunication system. A new »praktiker«, an Austrian magazine for multi- digital exchange allows simultaneous operation media and electronics, showed the Inmarsat-M of analog and digital trunked-radio channels. A radiophone SP1600 from Rohde & Schwarz on network operator can therefore continue to use the cover of its July/August 1995 issue and his existing Accessnet infrastructure and flexibly devoted an article to the purpose and use of integrate a modern digital system step by step. this modern radio system.

News from Rohde & Schwarz Number 150 (1996/I) 61 Final article

Rohde & Schwarz system support – there’s system to our service

FIG 1 The support hotline provides the user The choice of the test system is of favour of a Rohde & Schwarz test of Rohde & Schwarz test systems with competent course of vital importance in this con- system is a decision for quality and assistance. text. Rohde & Schwarz test systems reliability throughout the entire lifetime combine the advantages of Rohde & of the system. Schwarz measuring equipment as well as the latest achievements in hardware Another important aspect when choos- “This is the Rohde & Schwarz test and software with the know-how and ing the system supplier is the question system support hotline.” These words experience gained by the company of how high system availability in spoken by a friendly voice welcome over many decades. The decision in demanding everyday use and thus the callers of the hotline of our system sup- value of the investment made can be port (+49 89-4129-36 07) day and maintained over the period of amor- night. All customers who have opted tization and during the entire life cycle for a Rohde & Schwarz test system of the system. Rohde & Schwarz offers and longterm support of their system a wide range of customized service by means of a service agreement can Hotline agreements to guarantee system sup- resort to this hotline (FIG 1). port under any conditions. According

Repair Consulting to the Rohde & Schwarz system phi- For our customers, test systems are losophy, the high demand placed on valuable capital goods which allow System competence does not stop with system them to be successful in their respective development but is maintained during markets. When buying a test system the Spare Parts Update the operational life of the systems in question of when the capital invested terms of servicing (FIG 2). will have paid off is crucial. This ques- Calibration tion is closely linked to the availability Hotline support, continuous updating of the system. Only high operational of system software, fast replacement availability can ensure fast amortiza- and repair of equipment and modules tion. FIG 2 After-sales support should faults arise are essential pre-

62 News from Rohde & Schwarz Number 150 (1996/I) Final article

It ensures that any downtimes of the Customer system will be kept to a minimum and provides the following services:

R&S System Support • hotline service with a response time of 24 hours, • extended equipment pool with ex- Development Central Service Service Offices Calibration Subcontractors press dispatch, • express repair, • quick on-site support by local service engineer. requisites for high system availability. FIG 3 The customer can get in touch with a Rohde & Schwarz offers integrated central partner at Rohde & Schwarz. The extended service time option is solutions comprising both system hard- for customers whose working day lasts ware and software. All problems the longer than eight hours. We can extend customer might encounter during the the service time for their systems up operation of the system will be handled The after-warranty service is to ensure to 16 hours per day. by a central partner who is in close that the high system availability already contact with all relevant Rohde & achieved by the enhanced warranty The guaranteed availability option in Schwarz departments (FIG 3). service will be maintained after expiry conjunction with the calibration service of the warranty. It contains all the unit and the express support will assure the The service concept is of modular struc- blocks of the enhanced warranty ser- customer extremely high system avail- ture and consists of unit blocks provid- vice plus the following: ability after expiry of the warranty. ing a whole series of service products • repair of faults, and options for hardware and soft- • supply of software updates. All these services are based on the ware. Thus the customer will be able to competence and experience of the adapt the service to his specific systems The on-site startup service gives the Rohde & Schwarz system support staff, and needs: customer the on-site support of an expe- who look upon themselves as partners rienced system engineer during the crit- of the customers and whose chief ob- Period Services available ical phase of starting up the system. The jective is customer satisfaction. Perhaps Warranty Rohde & Schwarz system system engineer provides application we can soon welcome you with the period warranty (part of regular system service) support and assists the customer in all words: “This is the Rohde & Schwarz Enhanced warranty service matters relating to system handling and test system support hotline…”. Option: express support service which are usually encountered Werner Baumgärtel Option: extended service time during the startup period of a complex On-site startup service system. This support assures smooth Calibration service transition to efficient use of the system: After- After-warranty service warranty Option: express support • support in system handling and period Option: extended service time operation, Option: guaranteed • application support. availability Calibration service The calibration service is for checking the specified parameters of the system The enhanced warranty service sup- at regular intervals and correcting them plements the standard warranty ser- if necessary. It comprises the following vices of Rohde & Schwarz to satisfy services: already during the warranty period the • calibration at specified intervals in high demands placed on system avail- line with ISO 9001/EN 21001, ability and offers a service time of eight • traceability of calibration to nation- hours and a defined response time: al or international standards, • database-supported information • calibration reports and certificates, system with direct customer access, • on-site calibration possible. • hotline service, • access to a pool of spare modules, The express support is the ideal sup- • on-site repair, if required, plement both to the enhanced warranty • escalation procedure. service and the after-warranty service.

News from Rohde & Schwarz Number 150 (1996/I) 63 P . O.B.8 ROHD 0 1 E 4 & 69 · SCHW D - 81614 München ·T ARZ GmbH&Co. KG·Mühldor el. (+4 9 89) 4 fstraße 1 29 - 0 ·Fax(+4 1 5 · D - 8 1 671 München 9 89) 4 1 29 - 2 1 64

News from Rohde & Schwarz 150 · PD 757.1660.21