News from Rohde & Schwarz

Cost-efficient and portable radiomonitoring up to 3 GHz

EMC measurements – the right equipment for every application

Controlled RF amplifier for physical applications

1997/ IV 156 Number 156 1997/IV Volume 37

Compact, portable, yet professional: Radio- monitoring Miniport Receiver EB200 reliably detects every emission from HF to UHF. Together with Handheld Directional Antenna HE200 it can even determine the transmitter position. The clear-cut display of the receiver shows frequency, level and IF spectrum in alphanumeric and graphical form. Photo 43 017

Articles

Günther Klenner Miniport Receiver EB200 and Handheld Directional Antenna HE200 Radiomonitoring from 10 kHz to 3 GHz now with portable equipment ...... 4 Heinz Mellein PCS1900 System Simulator TS8915 Exclusive type certification of PCS1900 mobile stations in the US ...... 7 Volker Janssen; EMI test receivers from 5 Hz to 26.5 GHz Karl-Heinz Weidner Concept of EMI instrumentation has proven itself...... 10 Klaus-Dieter Tiepermann Signal Generator SMIQ + SMIQ-B42 Multichannel signal source for CDMA ...... 13 Horst Wolf 75 kW RF Amplifier VD741K1 High-power RF amplifier for physical applications ...... 16 Rainer Wießmeier DVB-T Modulator SDB-M Start into digital terrestrial TV...... 19

Application notes

Dr. Holger Heuermann Precise S-parameter measurements are the key to modelling electric circuits ...... 22 Franz Demmel; Networking digital direction finders for improving radiomonitoring Günter Hinkers efficiency and locating frequency-agile emitters ...... 24 Jörg Pfitzner; Wolf D. Seidl Planning and monitoring VHF and TV transmitters...... 26

Software

Thomas Kneidel; New PropWiz software makes shortwave link prediction Dr. Hans Waibel even more convenient ...... 28 Claus Holland Digital Direction Finder DDF190 goes RAMON ...... 29

Brand-new: standard DVB-T for digital terrestrial television, yet Rohde & Schwarz already has the suitable modulation source on hand (page 19); another innovation for DVB: optional input interface for TV Test Transmitter SFQ (page 34).

2 News from Rohde & Schwarz Number 156 (1997/IV) Refresher topic

Peter Hatzold Digital modulation and mobile radio (VII) ...... 30

Panorama

Thomas Reichel Insertion Units URV5-Z2 and URV5-Z4 for voltage, level and power measurements up to 3 GHz...... 32 Thomas Maucksch From dual-mode to multimode radiocommunication tester – IS-136 standard now implemented in CMD80 ...... 33 Peter Schmidt Optional input interface for TV Test Transmitter SFQ...... 34 Daniel Schröder ReFLEX25 and FLEX roaming in Signal Generator SME ...... 35 Norbert Linge; Rohde & Schwarz naval communications systems for Robert Träger joint Dutch-Spanish project ...... 36 Ekkehardt Claußen Passenger telephone system Jetcall 2000 up and away ...... 37

Regular features

Booktalk: Electromagnetic compatibility ...... 9 Günther Klenner Test hint: Simple bandwidth measurement in radiomonitoring ...... 15 Newsgrams ...... 38 Information in print ...... 40 Press comments ...... 41 Günter Hornauer Final article: D-channel filter – essential contribution to increased security of ISDN telecommunication systems ...... 42

New risks: going over to digital telephone and fax poses dangers for IT security. If you wish to know how to protect your ISDN telecommunication system against manipulations via PSTN, read our final article on page 42.

Imprint

Published by ROHDE & SCHWARZ GmbH & Co. KG Mühldorfstraße 15 D - 81671 Munich Telephone (0 89) 41 29-0 · international (+49 89) 41 29-0 · Editors: H. Wegener and G. Sönnichsen (German) · English translation: Dept. 5CL4 · Photos: S. Huber · Artwork: N. Hofmann · Circulation 100 000 four 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 156 (1997/IV) 3 Articles

Miniport Receiver EB200 and Designed for portable use Handheld Directional Antenna HE200 The ergonomic front panel of Miniport Receiver EB200 makes for convenient Radiolocation from 10 kHz to 3 GHz operation in portable applications (FIG 1). The connectors for antenna now with portable equipment and headphones are located on the left side of the front panel, providing an Radiolocation in the frequency range 10 kHz to 3 GHz has now become portable: unobstructed view of receiver settings. with Miniport Receiver EB200 and active Handheld Directional Antenna HE200 All settings can be made with one hand for searching and monitoring emissions, detecting interference and locating since all important keys and controls miniature transmitters even in difficult terrain – with performance characteristics are within easy reach without blocking so far unparalleled by equipment of this size. Moreover, when accommodated in out the graphic display, which not only a rack, EB200 is a cost-effective, compact receiver that can be remotely controlled furnishes alphanumeric information via LAN interface. but also displays symbols and spectra. Various display modes are available to allow for zoomed representation of parameters important for a given application (FIG 2). Digital recording and subsequent evaluation of emissions is possible by means of a recorder connected to EB200.

EB200 is powered from a battery pack (optional) plugged to the unit. The battery pack can be replaced easily and conveniently. It can be charged from the power supply unit and the integrated electronics while the receiver is powered from a second battery pack. The power-saving receiver concept enables about four hours of continuous operation, which is sufficient for most applications. 24-hour operation is possible with an additional, commercial battery belt for which EB200 has a separate connector.

FIG 1 With a weight as little as 4 kg, Miniport Receiver EB200 can conveniently be carried and operated, leaving one hand free for Directional Antenna HE200. Photo 43 016/1

4 News from Rohde & Schwarz Number 156 (1997/IV) Articles

The sturdy aluminum housing with- stands even major impacts without any damage. Because of its compact size it can be accommodated in the glove box of a car. Powered from the car battery (10 to 30 V), the receiver can be operated for several days since it requires less than 22 W. This also means that no blower is required so that the receiver – with the loudspeaker switched off – operates absolutely FIG 3 noiselessly. Receiver bank with six Miniport Receivers EB200

used for operating EB200. The receiver range varies to a greater extent than Frequency incorporates as a standard an input that of transmitters located far away. filter that tracks frequencies in the range This differential display allows the fast 20 to 1800 MHz. This allows undis- and reliable location of miniature trans- turbed reception of weak useful signals mitters even with spread-spectrum trans-

IF panorama even in the vicinity of powerful transmit- mission. ters. For the range 10 kHz to 30 MHz, EB200 can be fitted with an optional EB200 and Handheld Antenna HE200 external input filter. are an ideal combination for the determination of transmitter location. Level Optimally equipped for The handheld antenna helps to find the all operating modes direction of a transmitter, which is useful especially in difficult terrain where Fitted with the Frequency Spectrum even four-wheel drive DF vehicles have (DIGI-Scan) option, EB200 scans the no chance to get there. For long-term Level, zoomed frequency range of interest with digital monitoring, an adapter comes with control and displays the associated the antenna for mounting it on any com- FIG 2 EB200 offers optimum display mode for spectrum (FIG 4). Emissions detected mercial tripod. A high-sensitivity ampli- any application. can be seen at a glance. Aural monitor- fier accommodated in the antenna han- ing of the information is possible by simply pressing a softkey. EB200 then System-compatible goes to the DIGI-Scan listen mode. The for stationary use stored spectrum is displayed in the background, and the emission of inter- EB200 is a compact, budget-priced est can be selected and monitored by and high-quality solution for use in marking it with the frequency cursor. Scan mode stationary systems. Due to the small size of the receiver, a bank of six EB200 Location of miniature transmitters at units will take up no more space than a close range is possible in the differen- PC (FIG 3). This allows the configuration tial mode of the DIGI-Scan option. In of compact radiomonitoring systems this mode, the displayed spectrum is Listen mode including analyzers, direction finders stored as a reference. Current spectra and recorders. Networking via LAN are superimposed on the reference makes for simple cabling and fast spectrum, and any new signals or transfer of commands. Since EB200 variations in signal strength are clearly Differential mode is controlled by means of SCPI com- discernible as peaks. If the measure- mands, any existing control software ment is made with the distance, the FIG 4 Displaying, monitoring and detecting for Monitoring Receiver ESMC can be field strength of transmitters at close signals with DIGI-Scan option

News from Rohde & Schwarz Number 156 (1997/IV) 5 Articles

IF demodulation the spectrum, level and offset for Switchable IF filters A/D converter any signal. The broadband signals AF Coprocessor are however not demodulated. With Digital signal Digital Input filter RF frontend processor IF, AF the IF Spectrum option, virtually any Antenna Tracking filter Mixer Bandpass filter IF amplifier IF type of emission can be identified. Switch-selected Oscillators attenuator Synthesizer IF panoramic display A/D converter Coprocessor Future-proof with Digital signal Front panel processor digital signal processing LC display Control processor Keypad Embedded power PC Accommodating the functionality of a Controls Firmware Remote-control Rollkey interface Remote unit of much larger size in the compact RS-232-C control IEC625 or LAN EB200 has been possible through the use of LSI components and digital signal processing in the IF filters, Power supply DC/DC converter demodulators and synthesizer modules Battery pack (FIG 5). These design features give a wide variety of selectable bandwidths and demodulators and offer a future- FIG 5 Modular design of EB200 (green: digital requirements. EB200 demodulates as proof solution since additional func- data exchange; blue: analog RF, IF, AF) standard not only AM and FM, but also tions or special analysis methods can LSB, USB and CW. A telephone filter subsequently be integrated at the is not necessary since the AF filter customer’s by simply downloading automatically follows the bandwidth. them from a PC. Any new features and With extremely broadband signals improvements, too, can in this way dle detects even extremely weak emis- (up to 1 MHz), the IF Spectrum option be added to the receiver. With EB200, sions. Direction finding is very easy by comes into its own, adding five more the user will therefore always have a means of a synthetic tone whose pitch bandwidths, so that EB200 will display state-of-the-art instrument. corresponds to the signal level. Moni- Günther Klenner toring this tone and direction finding is possible at the same time by matching the tone to the signal contents. This tone is switched on also with pulsed transmitters, and level changes can be recognized by the change in pitch.

Signal evaluation is based on the sig- Condensed data of Miniport Receiver EB200 nal contents and the signal spectrum. Frequency range 10 kHz to 3 GHz Especially with digital transmission, the Dynamic range –10 to 110 dBµV spectrum is often the only means of Demodulation AM, FM, USB, LSB, CW identifying a signal without resorting to (further modes as options) more sophisticated analysis equipment. Bandwidths with demodulation 10 (150 Hz to 120 kHz) Since signals are emitted at different Bandwidths for signal analysis 15 (up to 1 MHz with IF Spectrum option) bandwidths, a fixed IF spectrum can Display full graphics, 240 x 64 pixels, backlit at best be a compromise. Therefore, Operator controls numeric keypad, softkeys, controls, rollkey an IF Spectrum option is offered for RF connectors for antenna, IF (10.7 ± 1 MHz), reference Audio connectors balanced, unbalanced, 600 Ω mono output, EB200 that allows variation of the stereo output, ext. loudspeaker, headphones resolution. This enables the signal spec- Digital connectors IF as I/Q signal, AF trum to be displayed at the optimum Remote control via RS-232-C, IEC625 or LAN (RJ45) interface, bandwidth in each case, and the user SCPI-conforming command syntax is always provided with the correct in- Dimensions of case 88 mm x 210 mm x 270 mm formation for evaluating the emissions Weight 4 kg; 5.5 kg with battery pack received. Continuous operation typ. 4 h with battery pack Power consumption <22 W Ten bandwidths from 150 Hz to Reader service card 156/01 120 kHz are available to cater for any

6 News from Rohde & Schwarz Number 156 (1997/IV) Articles

PCS1900 System Simulator TS8915 NATWG.03 [4] defines the procedure of GSM N.A. type certification for PCS1900 mobile stations. PCS1900 System Simulator TS8915 and Test Set Exclusive type certification of CRTC02 from Rohde & Schwarz are cited in this document exclusively as ref- PCS1900 mobile stations in the US erence platforms for type certification. This certification is based on the GSM The European mobile radio standard GSM is conquering the globe, and the US specifications including the correspond- market is an integral part of this development. Like in Europe, type certification ing modifications for the North Ameri- for mobile stations to PCS1900 has become obligatory since the middle of this can standard. These modifications are year. Rohde & Schwarz is the only company to offer the required test equipment: defined and maintained by the GSM PCS1900 System Simulator TS8915. N.A. network operators.

FIG 1 PCS1900 System Simulator TS8915 pro- System Simulator TS8915 (FIG 1) is The test specification is documented in vides more than 200 test cases for type certifica- based on Test System TS8915B [3] GTS (Global Telecommunications Stan- tion of US mobile phones to PCS1900 standard. Photo 42 284 which includes Digital Radiocommuni- dard) recommendation PCS 11.10-1, cation Test Set CRTC02. Thus, all re- derived from GSM 11.10-1 specifica- quired signalling tests and high-preci- tion. Rohde & Schwarz was involved at sion RF parameter tests are possible. a very early stage in the creation of this Besides the PCS1900 System Simulator test specification initiated by the Ger- In the US, the PCS1900 standard is TS8915 as a complete system for type man test house and service enterprise currently being drawn up within GSM testing, CRTC02 is accepted as an CETECOM [5] and implemented the N.A. (GSM North America) as a alternative platform for signalling tests test cases on PCS1900 System Simula- derivative of the European GSM stan- within type certification. tor TS8915 and Test Set CRTC02. Thus, dard phase 2 (in future also called within six months, more than 200 test GSM1900). PCS1900 stands for Per- On the way towards PCS1900 cases could be implemented and vali- sonal Communications System in the type certification dated in due time for the official start 1900 MHz band. Rohde & Schwarz on 1 June 1997. The test implementations has responded to this development in In line with CTIA (Cellular Telecommu- were again validated by CETECOM in good time by providing the correspond- nications Industry Association), the close cooperation with the developing test equipment [1; 2]. PCS1900 Permanent Reference Document PRD ment engineers from Rohde & Schwarz.

News from Rohde & Schwarz Number 156 (1997/IV) 7 Articles

After an initial phase of 18 months other Doc. File of Handset Manufacturer Additional Requirements • PCS 11.10 Test Report of for Type Certification independent test labs can be accredited accredited testhouse (FCC, SAR,…) by GSM N.A. for PCS1900 mobile • FCC station certification. During this phase, cooperation with other test houses is Common Understanding Admin for Type Certification possible. The PCS1900 Type Certifica- NATWG.03;NATWG.xx;Advisory Notes tion Review Board (PTCRB) defines the required test cases. Currently, the list Members: PVG PTCRB Certificate • administrator (PCS 11.10-1 contains 315 tests that will be available (PCS 1900 GSM NA and • operator Spec.) MoU Validation TWG by autumn this year. FIG 2 gives an Seal • testhouse Group) • (manufacturer) overview of the PCS1900 type certification process. ANSI Test GSM NA (T1P1.5), Equipment Standards ETSI Manufacture Differences between European GSM and GSM N.A.

Type certification of PCS1900 mobile FIG 2 PCS1900 type certification diagram work operators in the North American stations using the PCS1900 system (source [4]) PCS1900 world. All this is taken into simulator is via the air interface, ie via account by the corresponding signal- the radio channel between the mobile ling software. Another innovation is the and base station (simulated by the enhanced full rate vocoder (EFR) which system simulator). Corresponding mod- can also be supported by PCS1900 ifications by CTIA or GSM N.A. had to have been introduced to the network Simulator TS8915. be considered for the test equipment. management. The GSM standard First of all, PCS1900-specific frequen- defines the location area identifier for Test system configuration cies have to be adhered to. TABLE 1 determining the position of a base sta- gives an overview of all the frequency tion by three parameters: MCC (mobile The PCS1900 system simulator com- bands currently occupied in the digital country code), MNC (mobile network prises three CRTC02 units allowing mobile radio world according to GSM code) and LAC (location area code). simultaneous simulation of up to six standard (channel spacing 200 kHz). MNC is the network indicator. A mobile radio cells (base stations). mobile station in Germany (MCC 262), Moreover, Signal Generators SME02 Moreover, three power classes have for example, recognizes from the and SMP02 provide the necessary spu- been defined. TABLE 2 compares the MNC whether it is in D1 (MNC 01), rious signals as required for selectivity current standards. The PCS1900 system D2 (MNC 02) or in E1 network measurements. A fading simulator in the simulator considers these parameters (MNC 03). Because of the 2-digit BCD PCS band ensures a realistic simulation by a corresponding configuration of coding of MNC the number of network of the mobile radio channel by exactly the RF switching matrix [6]. Thus, the operators in the GSM standard is limited simulating standardized fading pro- complete frequency and level range to 99. This parameter was extended to files. Spectrum Analyzer FSM allows can be tested. Further modifications a value allowing to identify 999 (!) net- frequency-selective measurements of the stimulating end of the DUT – eg for spectral analysis of the transmit signal of the mobile station – as well as the Service Uplink Downlink Channel number TABLE 1 Mobile radio services and asso- frequency-selective analysis of spurious P-GSM 890 to 915 MHz 935 to 960 MHz 1 to 124 ciated frequencies emissions. Dual-Channel Power Meter E-GSM 880 to 890 MHz 925 to 935 MHz 975 to 1023 (P-GSM/E-GSM = Pri- NRVD can carry out high-precision mary/Extended GSM, DCS1800 1710 to 1785 MHz 1805 to 1880 MHz 512 to 885 level measurements due to the fully DCS1800 = Digital PCS1900 1850 to 1910 MHz 1930 to 1990 MHz 512 to 810 Communications automatic RF path compensation by System at 1800 MHz) the system itself. All relevant RF signals are applied to the DUT via a complex RF switching matrix. The required accu- Service Power classes Maximum power Minimum power TABLE 2 Power classes racies for the RF parameters of the test GSM 2, 3, 4, 5 39 dBm (8 W) 5 dBm of mobile radio signal are thus ensured for type testing. (approx. 3.1 mW) standards As an option TS8915 can also com- DCS1800 1, 2, 3 36 dBm (4 W) 0 dBm (1 mW) prise audio test equipment so that this PCS1900 1, 2, 3 33 dBm (2 W) 0 dBm (1 mW) type of testing is also possible.

8 News from Rohde & Schwarz Number 156 (1997/IV) Articles

The test requirements of PCS1900 REFERENCES [4] Permanent Reference Document NATWG.03 11.10-1 include the same test ranges as [1] Steffen, R.: Digital Radiocommunication Test for GSM N.A., Mobile Equipment Type Certification and IMEI Control those known from GSM or DCS1800 Set CRTC02 – Universal tester for GSM and DCS mobile phones. News from Rohde & [5] Reference test engineering from Munich for type testing. It is noteworthy that the Schwarz (1995), No. 149, pp 10–12 booming US mobile-radio market. News from system simulator – due to its flexible [2] Schneider, H.-J.: Automatic Functional Test Rohde & Schwarz (1997) No. 155, p 38 concept – is not only suitable for (Type Approval) of PCS1900 Base Stations. [6] Schneider, H.-J.: PCN Simulator TS8920 – PCS1900 type certification but also Proceeding of the Fourth Annual Wireless Upward-compatible test system for PCN for type testing of DCS1800 mobile Symposium, Santa Clara (Feb. 1996) mobile telephones from development to type stations. Corresponding test cases are [3] Rohde & Schwarz: Type Approval Systems approval. News from Rohde & Schwarz for Mobile Radio TS8915A/B (Info 4/96). (1993) No. 143, pp 4 –7 also available in the GSM band and so TS8915 is optimally prepared for final GSM type-approval testing. These Condensed data of PCS1900 System Simulator TS8915 characteristics make the simulator fit Frequency range (useful band) for providing multiband test cases Uplink 1850 to 1910 MHz without elaborate modifications being Downlink 1930 to 1990 MHz required: this means a single system Modulation GMSK suitable for all possible applications in Power (uplink) 1 mW to 4 W the GSM world. Reader service card 156/02 Heinz Mellein

Electromagnetic compatibility Booktalk

by Joachim Nedtwig and Martin Lutz (editors). principles of EMC are described and interference The handbook offers a wealth of information that The handbook “Electromagnetic Compatibility” source, coupling and interference sink explained. has not been compiled in such a comprehensive published by the German WEKA Fachverlag in way before. The expected penetration of electric Augsburg in the form of a loose-leaf edition was Volume 2 deals with the electronic and mechanical and electronic products into all spheres of life will printed for the first time in February 1996, when development of equipment from the viewpoint of make further EMC standards and legislation neces- it comprised around 700 pages. It has since EMC and provides an insight into EMC in motor sary. The handbook is published as a loose-leaf then been updated by six supplements and is vehicles and the interrelation of EMC and lightning edition and will be regularly supplemented (partly now available as a 1200-page edition including a protection in aircraft. One chapter is dedicated to also on CD-ROM), so it will be possible to keep the CD-ROM. It is available from WEKA Fachverlag the legal consequences of the EMC law. Two further compendium up to date at all times. AS für technische Führungskräfte GmbH, Morell- sections are provided for measurement and test pro- strasse 33, 86159 Augsburg, Germany; price: cedures according to EMI and EMS standards. The 298.– DM (only in German). contribution on electromagnetic interference measurements was made at Rohde & Schwarz by Dipl.- With the help of 30 experts, each contributing their Ing. Karl-Otto Müller, who over the past 20 years specialized knowledge on EMC, the editors have has been in charge of the development of R&S EMI created a publication covering all aspects of elec- test receivers, which are in use all over the world. tromagnetic compatibility for engineers and tech- nicians. Volume 1 of the compendium, which The handbook is rounded off by a section dealing by now consists of two volumes, deals with the with a cost and economic analysis of EMC testers. relevant EC directives, the implementation of EMC This section may help those who have to decide Directive 89/336/EEC in the form of the German between buying their own tester or having meas- EMC law and its implications as well as with the urements performed at a test house. A list with the EMC standards. It also lists the standards for the addresses of companies offering EMC services in protection of personnel and the low-voltage direc- the German-speaking countries and the relevant tive. In the last chapter of volume 1 the physical bodies and authorities is also provided.

News from Rohde & Schwarz Number 156 (1997/IV) 9 Articles

EMI test receivers from 5 Hz to 26.5 GHz implemented in the instrument firmware in the form of intelligent test routines, interactive macros and automatic evaluation functions. In addition, EMI soft- Concept of EMI instrumentation ware packages for commercial PCs allow automatic control of complete has proven itself EMI test systems via IEC/IEEE bus.

The adoption of the European EMC Directive 89/336/EEC at the beginning of the 90s The legal provisions prescribing com- has created a need for instruments that are able to perform accurate measure- pliance of devices or systems with ments in line with the applicable EN standard. Rohde & Schwarz took up this EMC (electromagnetic compatibility) challenge in time by introducing a new EMI test receiver generation in 1991. standards in all countries of the Euro-

ESPC ESHS10

9 kHz ESPCESPC 2.5 GHz ESVS30 ESHS30 9 kHz ESHS 10/30 30 MHz

20 MHz ESVS 10/30 1 GHz

ESCS30 9 kHz ESCSESCS 3030 2.75 GHz ESVS10

5 Hz ESSESS 1 GHz

ESBI/ESMI 20 Hz ESBIESBI 5.2 GHz

ESS 20 Hz ESMIESMI 26.5 GHz

FIG 1 Overview of spectrum of Rohde & ing with a CISPR quasi-peak detector pean Union since the beginning of Schwarz EMI test receivers demands on the one hand high immu- 1996 made it necessary to adopt a nity to overdriving and on the other new strategy for planning, develop- high sensitivity for RFI field-strength ment and assembly of electrical and Standard-conformal measurements of measurements that take into account electronic devices. EMC measurements interfering emissions (EMI) place high- cable losses and antenna correction are to be performed at all stages of est demands on the characteristics of factors, ie a dynamic range that can be development, construction and quality a test receiver which must be able to obtained only with the aid of advanced assurance through to market intro- correctly detect and evaluate pulsed circuit design. To further increase the duction and marketing of the ready-to- or sinusoidal, modulated or intermittent efficiency, time-saving test methods are sell product. Besides the test setups interferers. The necessary pulse weight- of great importance. They are mostly stipulated by EMC standards, precision

10 News from Rohde & Schwarz Number 156 (1997/IV) Articles

measuring instruments complying with houses, authorities and quality assu- EMI Test Receivers ESBI and ESMI CISPR 16-1 standard are a prerequisite rance departments of large companies. These test receivers are based on the for performing reproducible measure- principle of a spectrum analyzer, ie ments at the specified accuracy. EMI Test Receiver ESS they utilize the advantages of fast ESS [2] is the flagship of the EMI test sweeps for prescan measurements. receiver family. It covers the frequency These features are combined with the The instruments range above 5 Hz and offers all CISPR accuracy, selectivity, dynamic range and MIL bandwidths up to 1 MHz. The and sensitivity of a test receiver in a Basically, all measuring instruments in strength of this unit is its compact design single compact unit. The frequency line with the basic CISPR 16-1 specifi- combined with an extremely high sensi- range 20 Hz to 5.2 (or 26.5) GHz and cations meet the demanding EMI tivity and high pulse loading capacity. the technical concept make this receiver measurement requirements. Conformity Three RF input modules each using a type ideal for test houses, military appli- to EMC standards may be confirmed different mixing principle guarantee ex- cations, research and education as well by an independent, accredited organ- cellent RF characteristics. Because of its as aerospace industry. ization. All Rohde & Schwarz full-com- elaborate design, ESS is mostly used by pliance test receivers conform to CISPR test houses and EMC service providers. standards [1]. FIG 1 gives an overview Other main fields of application include Precertification sector of EMI test receivers and their fre- computer and car manufacture, quality quency ranges. assurance at large companies as well EMI Test Receiver ESPC as measurements up to 1 GHz in the ESPC was especially developed for pre- military sector. certification measurements. Although Full-compliance sector the unit has a slightly reduced function- EMI Test Receiver ESCS30 ality, it yet features a clearly higher EMI Test Receivers ESHS10 and ESCS30 [3], the latest member of measurement accuracy and reliability ESVS10 the test receiver family, offers a number of results than many other instruments of All test receiver of series 10 are able to of unique features making it an impor- its class. It is mainly used for develop- automatically control artificial mains tant extension to the family. Highlights ment-accompanying measurements in networks via macros and allow at the such as continuous frequency range all sectors of industry and for all types same time test reports to be output on a from 9 kHz to 2.75 GHz, colour LCD of products, but also in research and plotter or printer. Optional AC-supply- with VGA resolution for displaying education and even by test houses as independent battery operation makes traces along with an analog bar for an add-on unit. the instruments ideal for mobile, open- up to three parallel-operating detectors site measurements at EMC service pro- as well as time domain analysis for All Rohde & Schwarz EMI test receivers viders, test houses and technical inspec- assessing the time response of EMI are able to perform fast prescan tion authorities, and particularly for emissions are all packed into one com- measurements with the aid of parallel development and acceptance tests in pact receiver which, to top it, features detectors, store a great number of limit industry in line with EN 55011 to an excellent price/performance ratio. lines and compare measurement results EN 55022 standards. ESCS30 complies with all commercial with active limit lines. To increase EMC standards to CISPR and VDE. An the measurement accuracy, transducer EMI Test Receivers ESHS30 and advanced operating concept using correction tables may be taken into ESVS30 macros for fully or semi-automatic test account in the level display. EMI Test Test receivers of series 30 differ from runs combines convenient operation Receiver ESPC is the only exception models 10 mainly by a built-in, low- with fast and reliable receiver setting. regarding full compliance with EMI leakage screen, IF spectrum analysis Low weight, optional AC-supply-inde- standards. Being mainly intended for and built-in 3.5“ floppy-disk drive for pendent operation up to four hours precertification measurements, it is storing and calling measurement re- from internal batteries and the built-in not fully compliant to CISPR16 when sults, limit lines, correction tables and 3.5“ disk drive make ESCS30 ideal for evaluating pulsed interferers using the scan data records. They are equipped mobile operation. Users of ESCS30 are quasi-peak detector. in addition with a tracking generator national authorities, approval offices, for two-port measurements or for deter- test houses, EMC service providers and mining cable losses. Users of ESHS30 industrial EMC laboratories. It is partic- Accessories and software and ESVS30 are the same as those of ularly noteworthy that a large number model 10, but the main field of appli- of these receivers is used by the All Rohde & Schwarz EMI test receivers cation for series 30 instruments is ac- German Post and Telecommunications can be operated with a comprehensive ceptance testing at accredited EMC test Office (BAPT). range of accessories including artificial

News from Rohde & Schwarz Number 156 (1997/IV) 11 Articles

5 Hz 9 kHz 30 MHz 1 5.2 26.5 GHz REFERENCES 2.75 Frequency 20 Hz 20 MHz [1] Müller, K.-O.: Conformity of Rohde & ESHS 10 Schwarz EMI test receivers with CISPR standards now confirmed officially. News from ESHS 30 EMI Software Rohde & Schwarz (1995) No. 147, p 51 ESVS 10 ESxS-K1 [2] Müller, K.-O.; Stecher, M.: EMI Test Receiver ESVS 30 ESS: the world’s first instrument covering ESS 5 Hz to 1 GHz. News from Rohde & ESCS 30 EMI Software Schwarz (1992) No. 138, pp 8–10 ES-K1 ESBI [3] Janssen, V.; Keller, M.: EMI Test Receiver ESMI ESCS30 – Top in full-compliance testing. News from Rohde & Schwarz (1997) No. 154, pp 7– 9 [4] Janssen, V.: Softwaregestützte Messungen in FIG 2 Software packages for full-compliance Software Packages ES-K1 [4] and der EMI-Messtechnik und zu beachtende EMI test receivers ESxS-K1 [5] (FIG 2) – operating under Grenzen der Automatisierbarkeit. Kompen- dium 1996, EMC-Journal, pp 270 –274 Windows™ 3.1 or 95 on any commer- [5] Janssen, V.: ESxS-K1 – attractively priced cial PC with IEC/IEEE bus or PCMCIA Windows software for EMC measurements. card – perform all receiver settings for News from Rohde & Schwarz (1996) EMI measurements to standard. If exter- No. 151, pp 40 –41 nal extras like mast, turntable and slide- mains networks, active and passive way systems are also to be controlled, probes, inductive probes, preamplifiers, height and polarization parameters as current probes, absorbing clamps, test well as angle positions and positions of antennas for magnetic and electric absorbing clamps are accurately moni- fields, turntables, antenna masts and tored, set for subsequent measurements slideways for absorbing clamps. and stored. Volker Janssen; Karl-Heinz Weidner

Condensed data of EMI test receivers

Type Frequency range Preselection/ IF bandwidths Tracking gen./ Other extras Options Recommended preamplifier IF analysis extras

ESHS10 9 kHz to 30 MHz yes/yes 200 Hz/9 kHz no/no macros, battery none rechargeable batteries

ESHS30 9 kHz to 30 MHz yes/yes 200 Hz/9 kHz yes/yes macros, floppy none

ESVS10 20 to 1000 MHz yes/yes 9 kHz/120 kHz no/no macros, battery impulse-resistant attenuator rechargeable batteries up to 1 GHz ESVS30 20 to 1000 MHz yes/yes 9 kHz/120 kHz yes/yes macros, floppy none

ESS 5 Hz to 1 GHz yes/yes 200 Hz/9 kHz/120 kHz yes/yes macros, floppy, int. oven crystal frequency Magnetic Field 2 Hz to 1 MHz bal. input, MIL Pickup Coil HZ-10 measurements

ESCS30 9 kHz to 2.75 GHz yes/yes 200 Hz/9 kHz/120 kHz/ yes/yes macros, battery, battery-supplied controller, EMI software, 1 MHz floppy, time rechargeable batteries, pulse limiter domain analysis IF analysis, oven crystal reference, tracking gen. 9 kHz to 2750 MHz

ESBI 20 Hz to 5.2 GHz yes/yes 200 Hz/9 kHz/120 kHz up to 5.2 GHz/ 2nd RF input, none EMI Software ES-K1 10 Hz to 1 MHz no MIL measure- 6 Hz to 3 MHz (–3 dB) ments

ESMI 20 Hz to 26.5 GHz yes/yes 200 Hz/9 kHz/120 kHz up to 5.2 GHz 2nd RF input, tracking generator extension ext. mixer 10 Hz to 1 MHz (opt. 26 GHz)/ MIL measure- to 26.5 GHz (up to 110 GHz), 6 Hz to 3 MHz (–3 dB) no ments EMI Software ES-K1

ESPC 150 kHz to 1 GHz yes/no 200 Hz/9 kHz/120 kHz no/no macros, battery frequency extension pulse limiter, 9 to 150 kHz + IF bandwidth El. and Magn. Field 200 Hz, freq. extension Probe Sets 1 to 2.5 GHz, int. batteries HZ-11, HZ-14 Reader service card 156/03

12 News from Rohde & Schwarz Number 156 (1997/IV) Articles

Signal Generator SMIQ + SMIQ-B42 the corresponding setting menu of SMIQ, in this case with nine active Multichannel signal source for CDMA channels. The second forward link mode provides SMIQ is an extremely versatile instrument for the generation of digital modula- as many as 64 code channels. The tion. Fitted with the optional modulation coder and data generator, it is capable power of the pilot channel is freely of generating both TDMA and CDMA signals. Now a new, cost-effective software selectable; the powers in the other option is available that turns SMIQ into a powerful IS-95 CDMA signal generator. channels are uniform. This mode is With this option, SMIQ can simulate the transmit signals of base and mobile used to simulate maximum channel stations. usage of a base station, since the forward link contains a maximum of 64 code channels. Modulation data are supplied by a PRBS generator; in addition, simple data patterns (00.., 11.., 01..) are available. PRBS data are ideal for component testing, for example of amplifiers. Data patterns are used for basic tests on demodulators of mobile station receivers. With a chip rate of 1.2288 Mchip/s, the modulation data rate is 19,200 bit/s. Channel coding or interleaving is not performed by SMIQ.

In reverse link operation, SMIQ simulates the transmit signal of a mobile station. This signal comprises only one code channel. SMIQ performs orthogonal modulation stipulated by IS-95 as well as spreading of modulation data. In full-rate mode, an offset-QPSK- modulated signal with constant output power is generated. For measurements on the output stages of a mobile station, half-rate mode with power gating can be simulated. A switchable burst randomizer is integrated, which is of advantage in burst measurements. Like with forward link, PRBS data or simple data patterns can be selected as a data source. The modulation data rate FIG 1 Signal Generator SMIQ, versatile RF tion, where SMIQ simulates the transmit is 28,800 bit/s, the long code is set source for research, development and production signal of a base station, two modes are to zero. in digital mobile radio Photo 42 979/1 available. Mode 18 provides up to 18 code channels. Walsh code and data source can be set separately for each channel. The powers of the pilot chan- Simulation of signals nel and two further code channels (eg sync channel and paging channel) are With the IS-95 CDMA software option freely selectable in this mode. The other (SMIQ-B42), Signal Generator SMIQ code channels (usually traffic channels) (FIG 1) [1] supplies signals conforming have uniform power. This exactly con- to standard for testing IS-95 CDMA forms to IS-97 specifications for the FIG 2 SMIQ setting menu for forward link code transceivers. In forward link opera- “Base Station Test Model”. FIG 2 shows channels

News from Rohde & Schwarz Number 156 (1997/IV) 13 Articles

High-quality reference source

Signal generators are often used as a reference source, so the accuracy of the generated modulation signal is an important quality criterion. SMIQ meets these requirements with an extremely low error vector of typically 1%. This corresponds to a ρ factor of 0.9999 for the CDMA signal. In the case of a forward link signal with several code channels, this small error vector makes FIG 4 Spectrum of pilot signal measured with FIG 5 Spectrum of CDMA signal with nine for very low crosstalk between the code Spectrum Analyzer FSEA code channels channels. The purely digital generation and addition of the code channels in conjunction with the small error vector results in highly accurate setting of a pilot signal and of a signal with crest factor variation by modifying the channel powers. FIG 3 shows that nine code channels. The ratio of peak the number of active code channels the setting error for the code channel power to average power, ie the crest (forward link). powers is less than 0.1 dB. The time off- factor, which is critical for measure- set or phase difference between signals ments on power amplifiers, is greater Receiver measurements of different code channels is extremely than 10 dB for the nine-channel signal small. Typical measured values are 1 ns [2]. Measured at a bandwidth of SMIQ offers a variety of trigger modes or 0.3°. 30 kHz, the noise power of the for receiver measurements. Frame and adjacent-channel spectrum is 70 dB superframe clock as well as 2-s clock High spectral purity for below total channel power. Adjacent- are available as trigger output signals. amplifier measurements channel power is thus more than 20 dB Conversely, CDMA signal generation below IS-97 limit values for base sta- in SMIQ can be started by means of an Two characteristics of a signal source tions. external trigger. For use as an OCNS are of particular importance for (orthogonal channel noise simulator), measurements on the power amplifier Ideal signal source output frequency and chip clock can of a CDMA base station: a large and for component testing be externally synchronized, too. These selectable number of code channels setting facilities provided for the data and a frequency spectrum with low Excellent signal quality of SMIQ and source already allow a number of basic adjacent-channel noise power. Here, versatile setting facilities of CDMA tests to be performed on the receiver. SMIQ sets unique standards. FIGs 4 option make the unit an ideal source for With an extension of the CDMA option and 5 show the measured spectra of measurements on CDMA components (currently under development) it will of any type. Passive components, eg also be possible to measure the frame filters, cause deterioration of modula- error rate (FER) on base station receivers. tion quality through linear distortion. This requires generation of a reverse The good ρ factor of SMIQ is there- link signal with a length of several fore required to evaluate frequency- hundred frames. response errors and group-delay distortion of such components. In the case of An add-on to SMIQ which is of particu- active components such as transistors lar importance for FER measurements or amplifiers as well as mixers, the should not be left out: Fading Simulator effect of nonlinear distortion is pre- SMIQ-B14. This option turns SMIQ into dominant. Third-order nonlinearities a fully-fledged radio channel simulator result in intermodulation products in the with six propagation paths [3]. In terms adjacent CDMA frequency channel of accuracy, the fading option clearly (spectral regrowth). High spectral exceeds the stipulations of IS-97, while FIG 3 Verification of accurate code channel purity as offered by SMIQ is a must offering an enormous price advantage power setting by code domain power measurement using Spectrum Analyzer R3465 from for spectral regrowth measurements. compared to conventional RF fading Advantest A particular asset is the possibility of simulators.

14 News from Rohde & Schwarz Number 156 (1997/IV) Articles

The next step: REFERENCES [2] Tiepermann, K.-D.: CDMA signals – a chal- broadband CDMA [1] Klier, J.: Signal Generator SMIQ – High- lenge for power amplifiers. RF Design (1996) quality digital modulation up to 3.3 GHz. No. 9, pp 72– 78 News from Rohde & Schwarz (1997) [3] Lüttich, F.: Signal Generator SMIQ + SMIQ provides an extremely powerful No. 154, pp 4–6 SMIQ-B14 – Fading simulator and signal hardware platform for baseband generator in one unit. News from Rohde & generation. CDMA signal generation Schwarz (1997) No. 155, pp 9 –11 is effected in a chip rate range between 1 kchip/s and 7 Mchip/s (0.1 Hz Condensed data of Signal Generator SMIQ with CDMA IS-95 resolution). For baseband filtering, a Option SMIQ-B42 Nyquist filter with adjustable roll-off Frequency range 300 kHz to 3300 MHz factor can be used instead of IS-95 Chip rate filters. Further developments towards IS-95 standard 1.2288 Mchip/s SMIQ range 1 kchip/s to 7 Mchip/s broadband CDMA are therefore to Forward link to IS-95 and J-STD-008 be expected. SMIQ offers the great ad- Number of code channels 1 to 64 vantage that any extensions required to Fraction of power this effect come as software options of each code channel 0 to –30 dB, selectable for up to 4 channels Modulation data (19,200 bit/s) PRBS, simple data patterns and can thus be retrofitted very easily. Reverse link to IS-95 and J-STD-008 For chip rates above 7 Mchip/s, too, Modes full rate, half rate SMIQ is a good choice. With an RF Modulation data (28,800 bit/s) PRBS, simple data patterns ρ bandwidth larger than 50 MHz, the Modulation accuracy (pilot) >0.9995 vector modulator offers ample reserves Adjacent-channel power (pilot) typ. –75 dBc (at 30 kHz bandwidth) for externally applied I/Q signals. Reader service card 156/04 Klaus-Dieter Tiepermann

Simple bandwidth measurement in radiomonitoring Test hint

In radiomonitoring it is sometimes necessary to ITU Recommendation 443 defines signal band- only for display but also in the processor. The ana- determine the bandwidth of a signal. This is usually width at the 6 dB or 26 dB point. Section 3.4.2.2.4 lyzer program of the Evaluate option transfers the performed with a test receiver, but now Radio- of the ITU manual describes a method of band- stored data to the spreadsheet routine, where they monitoring Receiver ESMC with Software Pack- width measurement using a spectrum analyzer are processed as described in the ITU manual. age ESMC-RAMON can also be used for this task. with maximum hold function. ESMC provides an equivalent measurement in frequency scan mode. The signal of interest is scanned with a narrowband filter at small stepwidths. The signal levels are displayed in the overview window of ESMC- RAMON software. This window also contains the maximum hold function, so that only results with ESMC-RAMON maximum level are displayed. The signal bandwidth can easily be determined by means of lines and markers. Radiomonitoring Receiver ESMC provides very In addition to this level-based bandwidth measure- good results for simple, manual bandwidth deter- ment, an example of power-related measurement mination as described above. For fast, automatic is given in Annex 1 to Section 3.4 of the ITU man- bandwidth measurements, a test receiver, eg ual. This example defines the bandwidth limit at ESVN40 from Rohde & Schwarz, is the obvious 0.5% of the signal power. This type of bandwidth choice. Günther Klenner measurement, too, can be performed by means of Receiver ESMC, Software ESMC-RAMON, the Evaluate option and a spreadsheet routine. The signal is scanned in the same way as in level-based Reader service card 156/05 for further ESMC bandwidth measurement, but data are stored not information on ESMC

News from Rohde & Schwarz Number 156 (1997/IV) 15 Articles

75 kW RF Amplifier VD741K1 means of optical fiber cables. Any high- voltage accidents are thus excluded right from the start. The amplifier can High-power RF amplifier be fitted, and also retrofitted, with klystrons of different make. So every for physical applications user can choose the klystron of his preference and change over to another Physical applications in the field of particle acceleration and synchrotron radiation product during the life of a system. For sources require safe high-power amplifiers with simple, reliable control, regu- applications requiring powers above lated amplitude and stable phase position. This is the domain of 75 kW RF 75 kW, several amplifiers can be com- Amplifier VD741K1 from Rohde & Schwarz. bined. Moreover, the power of a single amplifier can be boosted up to 150 kW through the use of a special klystron With RF Amplifier VD741K1 (500 MHz), system according to their functions: con- and a larger collector supply. Rohde & Schwarz is adding another trol unit in the operator room, collector component to its range of transmitter power supply at the AC supply inlet, and Applications equipment (FIG 1). The amplifier essen- RF generator next to the RF load. In gen- tially consists of a klystron for RF power eral, there is not enough space to set up The essential criterion determining the generation, to which various modules all the amplifier components at any one use of the amplifier is what might are assigned that can be set up sepa- of these locations. Special site planning be referred to as the “experimental rately from the klystron, ie cooling-water of the system components may also be environment”. This means that, apart supply, high-voltage supplies, collector necessary if, for example, air coolers from the definition of limit values for the power supply as well as control cabi- are not to be used in order to save costs. various parameters, all intermediate net. This is invaluable for systems taking values too play a role for the experi- up a lot of space such as particle accel- The klystron is safely protected without ment on hand and must therefore be erators or storage rings. The modular the use of a high-voltage crowbar. The settable and controllable. Moreover, concept of the amplifier thus allows the connections between high-voltage sec- the output values need to be controlled various components to be set up in the tion and control section are made by automatically rather than manually. RF Amplifier VD741K1 offers the following characteristics:

• selection of output power from 75 W to 75 kW, • adjustable, regulated, constant RF amplitude at load, ie at the cavity of the storage or accelerator ring, • resonance-tuning of cavity, • absorption of reflected power of cavity from 0 to 100%, • variation of operating point of klystron to save energy in cases where maximum power is not required.

Thanks to graphical status display, minimum operator control and high accuracy and stability of the regulation and control circuits, all of the above functions can be performed without the support of an RF expert on site. The FIG 1 Control cabinet amplifier also informs the user of the of 75 kW RF Am- causes for activating cavity, klystron plifier VD741K1 or personnel protection against RF or (not including other forms of high energy. It further re- collector power supply) quests a change of experimental condi- Photo 43 020 tions, where necessary, and indicates Articles

FIG 2 Control and Manual the command RF ON will trigger all the SPC network of display unit control required sequences up to emission of RF Amplifier System control Communication 1.8 to 4.5 km High-speed bus VD741K1 processor (10 Mbit/s) the preset RF level, including preceding Stored- functional testing of all safety-relevant program CAN bus (field bus) control Profi bus (field bus) amplifier components. Operational se- (10000 ctrl commands, TTY (9.2 kbit/s) 96 KB memory quences are shown quasi-graphically capacity) RS-232-C (9.2 kbit/s) on the control and display unit (FIG 3). RS-485 (76.8 kbit/s) The nominal values for the operational Collector power supply Operational-data monitoring option sequences can be set on the control Stored- Stored- CAN bus program program control and display unit. As a default setting, control (1000 ctrl commands, Optical (1000 ctrl commands, 9.6 KB memory Profi bus the values for maximum output power 9.6 KB memory capacity) cables capacity) are selected. Any other values can be Dig. Dig. Anal. Anal. Dig. Dig. Anal. Anal. Dig. Dig. Anal. Anal. in out in out in out in out in out in out set over the complete dynamic range; any values not permissible for reasons of safety will be recognized and reject- Measured values, nominal Measured values, nominal Operational data values, commands, messages values, commands, messages ed. The amplifier can thus be operated virtually without requiring any basic knowledge of klystron functions on the any supply faults (water, air or power • dissipated-power optimization of part of the user. supply, temperature) as well as defec- amplifier through appropriate selective modules. Experiments can also be tion of klystron operating point (set- Safety measures performed automatically. To this end, ting of collector and anode voltage the amplifier can be integrated into a for intended output power), Safety comprises two essential com- control bus configuration using, for • monitoring of all nominal and actual ponents: safety for personnel and pro- example, field buses such as CAN or values, tection of critical system parts against Profi, which operate simply and reli- • warning without lowering of RF damage caused by maloperation or ably over the large distances of a par- levels in the event of abnormal oper- malfunction. ticle experimentation system. ating states or acceptable out-of- tolerance parameters, Personnel safety is implemented in Control and operation • storage of causes of automatic RF or Amplifier VD741K1 by applying the AC supply switch-off, proven concepts of the Rohde & The amplifier optimally performs all of • communication with high-voltage Schwarz sound and TV broadcasting the above tasks with its stored-program circuits (collector supply) via optical transmitters. These include: controls (SPCs). Apart from system cables, control, a further SPC is provided in the • communication with control and dis- • emergency shutdown, collector power supply and one in play unit, operational status display, • positively operated door switches in the operational-data monitoring unit acceptance of new nominal values, the high-voltage and AC supply inlet (FIG 2). All these units are networked. output of warnings and error mes- areas (for blocking of AC supply), The operational-data monitoring unit sages, can thus be offered as an option and • communication with programming the collector power supply as an inde- unit for program analysis or step-by- pendent unit. The SPC network has the step program run, following functions: • linking of amplifier to bus systems (CAN and Siemens Profi field buses, • testing of all safety-relevant amplifier Siemens H1 high-speed bus), components upon power-up (if am- • communication via interfaces plifier is switched on several times a (RS-485, RS-232-C, TTY). day, a short test is run), • sequence-controlled RF switch-on, Operator control of the amplifier is re- • RF amplitude stabilization to digital duced to a minimum. The hierarchical setpoint value by regulation of RF states AUX ON (auxiliary supplies on), input level, HV ON (high voltage on) and RF ON • RF amplitude stabilization to digital are activated at the push of a button.

setpoint value by regulation of anode A higher state in the hierarchy encom- FIG 3 Status indication of control and display modulator voltage of klystron, passes all lower states. For example, unit

News from Rohde & Schwarz Number 156 (1997/IV) 17 Articles

• separate emergency switch for the fault. Similar actions are taken to ie primary-circuit thyristor control of a amplifier, protect the RF-fed cavities in the storage high-voltage transformer with a choke • lockable grounding switch; key for and accelerator ring. An action will be connected in the neutral point. The AC opening high-voltage section access- triggered in the event of arcing, poor supply is filtered effectively so that the ible only after grounding, vacuum or defective vacuum pumps, output signal contains only 0.1% of the • grounding rods in high-voltage for example. fundamental. section, • interlock circuits connecting all In addition to these high-speed actions, The control cabinet comprises the modules and cables. the SPC of the system control checks system control, control and display unit, and analyzes all values and commands instrument panel, floating auxiliary The above measures ensure enhanced entered. Monitoring also covers power, supplies, operational-data monitoring, safety for personnel, who themselves water and air supplies, common opera- optical-cable communication interface, can do one more thing by applying tional parameters, power supply and RF processing section with amplitude the five golden rules of electrical safety; distribution units, communication net- and phase control, RF preamplifier, RF the amplifier is appropriately equipped work, operability of auxiliary supplies demodulators, RF control circuits and for this. and modules, and a large number of cavity resonance tuning. interlock circuits in the amplifier compo- Safety for the klystron is ensured with- nents. The operating speed of the SPC The high-voltage cabinet accommo- out the use of a high-voltage crowbar. is in the 100 ms range, so analysis will dates all auxiliary supplies and test In the event of a high-voltage short cir- produce rapid information, warning or points of the klystron that are at high cuit in the klystron, the energy released switching to a lower hierarchical state, potential, as well as the high-voltage in the klystron is limited to 10 Joule. This ensuring that the amplifier is always circuit. The klystron can be cut off from is achieved through appropriate dimen- in a safe operating state. In the event high voltage at all connecting points via sioning of the high-voltage circuitry and of a failure of the SPC itself (time-out), grounding switches. rapid switch-off of RF and high voltage. any supply voltages to the amplifier are The thyristor regulator is disabled automatically disconnected. The klystron is mounted on a trolley and the inductance on the power line and set up with a supply rack for cool- discharged. For fast and reliable trig- Amplifier components ing water and cooling air separately gering of this protection mechanism, from the other amplifier components. the following test points are provided: The collector power supply (30 kV, The RF is taken to the circulator via the 6 A) operates on the principle known common RF test points. • high voltage, from Rohde & Schwarz TV transmitters, Horst Wolf • current, • current rise (arcing), • loading of klystron body (focusing fault), • RF arcing in klystron or circulator, • klystron input power (to prevent overloading/saturation), • auxiliary supply of klystron (focusing).

The test points trigger the required Condensed data of 75 kW RF Amplifier VD741K1 safety actions via optical cables and Ω 1 1 are interlocked, so that the cause of an RF output power 75 W to 75 kW into 50 (EIA 6 /8“/SMS 6 /8“) Level setting range 13 dB (via predefined nominal value) action can be identified unambiguously Dynamic range of control 30 dB in each case. The SPC of the system RF input 0 dBm into 50 Ω (N) control reads the actions taken and out- 1 dB bandwidth 0.5 MHz puts an analysis thereof on the control VSWR 1.4 (∞ with circulator) and display unit. SPC initiates and con- Power consumption 200 kVA trols all further actions required until the AC supply voltage 3 x 400 V amplifier is ready for operation again. Control locally via control and display unit or via interfaces Until the output of a start command, the Interfaces CAN bus, L2 bus, TTY, RS-485, RS-232-C amplifier remains in the highest hierar- and other interfaces chical operating state possible without Reader service card 156/06 any risks or danger upon occurrence of

18 News from Rohde & Schwarz Number 156 (1997/IV) Articles

DVB-T Modulator SDB-M • analog IF output for driving high- power transmitters, • optional upconverter with output frequency adjustable from 47 to 860 MHz and 0 dBm output level, Start into digital terrestrial TV • SFN (single-frequency network) option for time and frequency synchronization in SFNs, including MIP Almost simultaneously with the adoption of the new terrestrial TV standard (megaframe initialization packet [3]) Rohde & Schwarz is introducing a matching digital modulation source: DVB-T decoder for optional automatic Modulator SDB-M which is equally suitable for use with high-power TV trans- configuration of modulator via data mitters and as a test transmitter in laboratories and production. input,

The high demands to be met by the terrestrial digital TV transmission standard DVB-T [1] are manifold: high program capacity is required in conjunction with excellent picture quality as well as transmission of data for supplementary services. Other requirements are highly reliable transmission even at low receiving field strengths and an excellent frequency management that leaves sufficient room for other radio services of the present and the future. All this is achieved by processing source-coded MPEG2 signals, adding a highly efficient error correction code, which takes into account the characteristics of the transmission channel, and the use of OFDM (orthogonal frequency division multiplexing) permitting single-frequency networks with widely spaced transmitters.

DVB-T Modulator SDB-M (FIG 1) was developed for use in high-power TV transmitters and as a test transmitter in the development and production of DVB-T components. Its distinguishing characteristics and parameters are: FIG 1 DVB-T Modulator SDB-M and solid-state • integrated PRBS (pseudo random TV Transmitter NH520 – ideal partners for terres- binary sequence) generator for BER trial digital TV Photo 42 961/1 • functions fully compatible with ETS (bit error rate) measurements, 300 744 [2], • test mode permitting energy disper- • LVDS (low voltage differential signal- sal, Reed-Solomon coder, bit inter- ling) input interface with data rates • OFDM with 2k or 8k mode, leaver and frequency interleaver to from 5 to 40 Mbit/s depending on • guard intervals of 1/4, 1/8, 1/16 be disabled individually, selected transmission parameters, or 1/32 of symbol period select- • parallel interface with floating con- • code rates 1/2, 2/3, 3/4, 5/6 or able, tacts for signalling or integration in 7/8 selectable, • digital I/Q modulation to prevent interlock circuits, • modulation modes QPSK, 16QAM phase errors, • serial interface for configuration via or 64QAM selectable, • 12-bit digital/analog converter with standard PC using the convenient • optional hierarchical modulation, 27.43 MHz sampling frequency, user interface supplied.

News from Rohde & Schwarz Number 156 (1997/IV) 19 Articles

TPS data

Frame sync

Low-priority error correction

Outer Energy Outer Inner Data Imag. Interface inter- t stream dispersal coder coder leaver Data Inner Frequency I/Q- Signal Real Frame Digital D/A IF SAW RF inter- delay Mapper interleaver IFFT modu- Amplifier ranspor adapter filters converter mixer filter mixer T leaver lator Outer MIP Energy Outer Inner Clock inter- decoder dispersal coder coder Clock Clock leaver

High-priority error correction SERBUS

Reference Synthe- VCXO frequency sizer 10 MHz 1 s clock Controller (eg from GPS receiver) IF RS-232-C 10 MHz Local IF RF

FIG 2 Block diagram of DVB-T Modulator SDB-M (options in blue)

Function derived for further processing (FIG 2). forwards them to the system controller The transport packet may have a length for further processing. The MPEG2 data and control signals of 188 or 204 bytes. An optional at the LVDS input interface are regener- MIP decoder separates the data of the For energy dispersal the data are ated and the required clock frequencies megaframe initialization packet and linked to a PRBS sequence so that an even power distribution is obtained in the transmission channel. The outer coder uses a shortened Reed-Solomon IFFT mode 8k 2k code (204, 188, t = 8) which adds Number of subcarriers 6817 1705 16 bytes to each transport packet for Symbol period 896 µs 224 µs error control, allowing up to eight TABLE 1 Carrier spacing 1116 Hz 4464 Hz errored bytes to be corrected in each OFDM parameters Useful bandwidth 7.61 MHz 7.61 MHz for 2k and 8k mode transport packet. A convolutional interleaver distributes the data in the form of bytes to twelve blocks to improve cor- Modulation Code rate Guard interval rection of several successive errors. The 1/4 1/8 1/16 1/32 inner coder operates bit by bit and 1/2 4.98 5.53 5.85 6.03 generates a punctured convolutional 2/3 6.64 7.37 7.81 8.04 code with code rates of 1/2, 2/3, QPSK 3/4 7.46 8.29 8.78 9.05 3/4, 5/6 or 7/8. 5/6 8.29 9.22 9.76 10.05 7/8 8.71 9.68 10.25 10.56 Two sets of the mentioned error correc- 1/2 9.95 11.06 11.71 12.06 tion blocks are available for hierar- 2/3 13.27 14.75 15.61 16.09 chical coding (option) allowing the dif- 16QAM 3/4 14.93 16.59 17.56 18.10 ferent data (programs) of the MPEG2 5/6 16.59 18.43 19.52 20.11 TABLE 2 transport stream to be transmitted with Input data rates in 7/8 17.42 19.35 20.49 21.11 either high error correction and low Mbit/s with non- 1/2 14.93 16.59 17.56 18.10 data rate (high priority) or with low hierarchical coding 2/3 19.91 22.12 23.42 24.13 depending on error correction and high data rate 64QAM 3/4 22.39 24.88 26.35 27.14 modulation, code (low priority). rate and guard 5/6 24.88 27.65 29.27 30.16 interval (values round- 7/8 26.13 29.03 30.74 31.67 The inner interleaver distributes these ed to two digits) data to a maximum of six serial bit streams (bit interleaving) depending on

IFFT mode 8k 2k modulation and code rate: two (QPSK), four (16QAM) or six (64QAM) bit Guard interval 1/4 1/8 1/16 1/32 1/4 1/8 1/16 1/32 streams with non-hierarchical coding, Symbol period 896 µs 224 µs or two (QPSK) streams for high-priority Guard interval 224 µs 112 µs 56 µs 28 µs 56 µs 28 µs 14 µs 7 µs data plus two (16QAM) or four Symbol period + 1120 µs 1080 µs 952 µs 924 µs 280 µs 252 µs 238 µs 231 µs guard interval (64QAM) for low-priority data with hierarchical coding. From these serial TABLE 3 Values for symbol period and guard interval bit streams, words with a width of two,

20 News from Rohde & Schwarz Number 156 (1997/IV) Articles

four or six bits are formed, which The required local frequency is gener- The integrated controller configures the determine the vector of a subcarrier. In ated internally but can be locked to a individual modules of DVB-T Modulator 2k mode, 1512 of these words form frequency standard or applied from an SDB-M power-failure-proof, monitors a symbol (6048 in 8k mode) and external source. their operation and provides informa- their position within the symbol will be tion at a parallel and a serial interface. scrambled (symbol interleaving). A synthesizer with upconverter is used At the serial interface this information for optional conversion to an RF output can be called up under Windows™ In SFNs, the different delays of the frequency. It converts the 7.61 MHz using a standard PC and the con- transport stream feeders to the transmit- wide OFDM signal to an adjustable venient user interface supplied (FIG 3). ters can be compensated by means of center frequency from 47 to 860 MHz Moreover, any parameter can be an optional signal delay. Differences of at an excellent S/N ratio. modified at this interface. up to 1000 ms with 100 ns resolution Rainer Wießmeier can be compensated manually or Selection of operating automatically by comparing the time parameters and operation stamp in the transport stream with an external 1 Hz reference. The input or net data rate is determined by setting code rate, modulation and REFERENCES In the mapper, the words are Gray-cod- guard interval. The selection of code [1] Lauterjung, J.: DVB-T, the new terrestrial TV ed and represented at the constellation rate and modulation enables a trade-off standard. News from Rohde & Schwarz (1997) No. 155, pp 31– 32 points of the complex level. The frame between the added error correction [2] ETS 300 744: Digital Video Broadcasting adapter adds 176 (701) subcarriers as code and the useful transmission (DVB); Framing structure, channel coding sync information in 2k mode (8k mode) capacity (TABLE 2). Selection of IFFT and modulation for digital terrestrial tele- and 17 (68) subcarriers as control infor- mode and guard interval depends on vision (DVB-T). ETSI (March 1997) mation so that a total number of 1705 the network structure and is dictated [3] ETS 101 191: Digital Video Broadcasting (6817) carriers is obtained (TABLE 1). by multipath reception (echo signals, (DVB); DVB mega-frame for single frequency network (SFN) synchronization. ETSI (April SFN transmitter at any distance to the 1997) Inverse fast Fourier transform (IFFT) receiver) for which the delay differences [4] Acts Validate: Implementation Guideline for converts the subcarriers represented at must be shorter than the guard interval DVB-T; Transmission aspects. Draft (April the complex level from the frequency to (TABLE 3)[4]. 1997) the time domain. During the guard interval of 1/4, 1/8, 1/16 or 1/32 of the symbol period, the beginning of the symbol is repeated with the respective length.

After forming a spectrum by means of digital filters and subsequent digital I/Q modulation, the time signal is applied to the D/A converter where it Condensed data of DVB-T Modulator SDB-M is converted to an IF of 35.764 MHz. Input data rate 5 to 40 Mbit/s, depending on operating mode IFFT mode 2k and 8k Modulation QPSK, 16QAM or 64QAM Guard interval 1/4, 1/8, 1/16 or 1/32 Inner code rate 1/2, 2/3, 3/4, 5/6 or 7/8 Inputs Transport stream MPEG2, LVDS, 25-contact sub-D, female, 100 Ω Reference frequency 10 MHz, –10 to +10 dBm, BNC, 50 Ω Outputs IF, COFDM 35.764 MHz, –7 dBm, BNC, 50 Ω or RF (option) band I to V, 0 dBm, BNC, 50 Ω SFN mode (option) to SFN-DS MIP data read-out via serial interface TS delay <1000 ms, automatic or manual setting Reference pulse input 1 Hz, TTL, BNC Interfaces serial RS-232-C, 15-contact parallel sub-D Reader service card 156/07 FIG 3 User interface of DVB-T Modulator SDB-M

News from Rohde & Schwarz Number 156 (1997/IV) 21 Application notes

Precise S-parameter measurements are the key to modelling electric circuits

the through-connection which leads to dependent equations for the corrective parameters. The following results show, however, that this only plays a minor role in practice.

To determine the measurement accuracy of Vector Network Analyzer ZVR in the frequency range from 10 MHz to 4 GHz, a high-quality coaxial PC7 air line from Rosenberger Hochfrequenz- technik* was employed for calibrating the ZVR.

In different verification measurements using the precision PC7 line system, the 63.5 mm long air line behaves like a T standard at lower frequencies and around 2.36 GHz:

c0 f = ; n = 1. 2 · n · 63.5 mm

FIG 1 Vector Network Analyzer ZVR used by calibrate a vector network analyzer As already mentioned, the TRL tech- Rosenberger Hochfrequenztechnik as precisely as possible is illustrated by nique does not call for a known reflec- Photo: Schröck-Freudenthaler the following simple example: a well- tion standard. Reflection standards matched DUT (return loss 20 dB) is to be measured and modelled. To carry out this task to approx. 0.8 dB or 5° accuracy, the analyzer must have a 0.05 directivity of more than 40 dB. In this dB High-precision S-parameter measure- case, matched loads cannot be used as 0 ment is the basis for characterizing a calibration standards since their return Magnitude -0.05 circuit component. The outstanding loss is not sufficient. 0.5 1 1.5 2 2.5 3 3.5 4 GHz measurement accuracy of Vector Net- Frequency work Analyzer ZVR from Rohde & Only precise lines can be used as im- -179.5°

Schwarz [1] offers the possibility of pedance standards for such measure- -180° efficiently modelling well-matched ments. ZVR supports the use of lines Phase

DUTs. Precision measurements call for with calibration technique TRL (thru, -180.5° 0.5 1 1.5 2 2.5 3 3.5 4 GHz ultra-modern calibration techniques reflect, line) [2]. Besides direct connec- Frequency and high-quality calibration standards tion of the two test ports and a precise along with excellent hardware. reference line, this technique requires a FIG 2 Reflection characteristic of short after TRL reflection standard whose S-parameters correction in Vector Network Analyzer ZVR All modern network analyzers claim need not be known. These calibration very high measurement accuracy since standards can be produced very the S-parameters are displayed with precisely in both planar and coaxial an extremely flat frequency response. line systems. Difficulties with the TRL * The company based in Upper Bavaria was Unfortunately, this is a fallacy as pre- technique occur if the line has a length founded in 1958 and has become a leading λ cision measurements still call for sound of n · /2. In this case, the line shows manufacturer of coaxial connectors and test background knowledge. The need to the same electric characteristics as equipment for high-frequency applications.

22 News from Rohde & Schwarz Number 156 (1997/IV) Application notes

0 0.5 dB (FIG 3). The consequences of limited dB -10 measurement capability at 2.36 GHz -0 -20 are illustrated by FIG 4 which shows -30 the verification measurement of a 25 Ω -0.5 -40 Magnitude Magnitude precision air line used as DUT. The re- -50 -1 sult – just like that in FIG 3 – also shows -60

-70 that the ZVR measurement accuracy is -1.5

-80 extremely good at 10 MHz although λ -2 -90 measurement is very close to 0 · /2. 0.5 1 1.5 2 2.5 3 3.5 4 GHz 0.5 1 1.5 2 2.5 3 3.5 4 GHz Frequency Frequency A very popular verification measurement

FIG 3 Reflection characteristic of second air is the ripple test [4] in which a 300 mm FIG 5 Reflection characteristic of 300 mm long line after TRL correction in ZVR long precision air line terminated with a air line terminated with short after TRL correction in ZVR short is measured (FIG 5). Calibration with opens or shorts of finite goodness shows instead of a linear curve a clear with the same electric characteristics superimposed ripple which is twice have to be measured at both test ports the attenuation of this long air line. This ZVR is an ideal platform for modelling during calibration. For the “sexless” ripple also helps to make conclusions electric circuits and components to an PC7 system, this requirement can be regarding network analyzer matching. accuracy of a few degrees. met with high precision since the same The ripple invisible here attests the Dr. Holger Heuermann standard can be contacted at both excellent quality of the ZVR hardware. (Rosenberger Co.) analyzer test ports (FIG 1). Therefore, the calibration standard requirements of TRL technique are almost perfectly met. The only shortcomings are the finite reproducibility of contacts which 0 are better than –70 dB for PC7, the dB -5 phase stability of the test cable (0.1° REFERENCES -10 short-time stability for precision cables) [1] Ostwald, O.; Evers, C.: Vector Network -15 and the deviations from ideal air-line Magnitude Analyzer Family ZVR – To the heart of the -20 geometry values. The latter are around chart. News from Rohde & Schwarz (1996) -25 No. 150, pp 6 –9 2 µm and limit the return loss of air lines -30 [2] Engen, G. F.; Hoer, C. A.: Thru-Reflect-Line: to approx. 60 dB. -35 An Improved Technique for Calibrating the Dual Six-Port Automatic Network Analyzer. -40 Shorts can also be produced as pre- 0.5 1 1.5 2 2.5 3 3.5 4 GHz IEEE Trans. MTT-27 (Dec. 1979) No. 12, Frequency cisely as air lines. Since a precision pp 987-993 short in the TRL technique is never used [3] Rohde & Schwarz: Measurement uncertain- Ω ties for vector network analysis. Application as a calibration standard, it is good for FIG 4 Reflection characteristic of 25 air line after TRL correction in ZVR Note 1EZ29_0E (Oct. 1996) verification. FIG 2 shows a TRL-corrected [4] Rosenberger: Streuparametermessungen in reflection measurement of a short. koaxialen Leitersystemen. Application Note Given the small deviations of the reflec- TI020/26.07.96/D1.0 (July 1996) tion measurement of 0.01 dB and 0.1°, ZVR can be concluded to have an effective matching of more than 55 dB after Excellent quality of the hardware and system error correction [3]. system error correction software of ZVR is confirmed by all four verification This excellent matching value can also measurements performed in the preci- be determined directly through the sion PC7 line system to analyze the measurement of a second air line. This measurement accuracy of Vector Net- measurement is thus ideal for verifica- work Analyzer ZVR after TRL calibration since narrowband effects such as tion. The minimal errors found can be the (n ·λ/2) errors can be analyzed fully attributed to the finite performance very precisely. It can be seen that data of the calibration elements, verifi- Reader service card 156/08 for further informa- matching drops to 30 dB at 2.36 GHz cation elements and test cables. Thus, tion on ZVR

News from Rohde & Schwarz Number 156 (1997/IV) 23 Application notes

Networking digital direction finders for improving radiomonitoring efficiency and locating frequency-agile emitters

The rapidly increasing variety of com- ability is achieved. Since one or several munication media and growing short- direction finders can also be remote- ness of suitable DF sites require wide- DDF0xM units DDF0xM units controlled from different operator posi- area networking of DF instrumentation PC with Windows NT PC with Windows NT tions, full-area direction finding can be and operator positions of large radio- performed with very few personnel. monitoring systems. A condition for The position of the transmitter can be networking is that the detected data are Wide-area network, eg ISDN calculated from the bearings of several reduced and processed at the DF site detached stations and marked on a considering that an extremely large digital map. volume of raw data is obtained by the MMI MMI direction finder when frequency-agile PC with Windows NT Location software DDFLOC signals and short-term emissions are monitored. Rohde & Schwarz has DDFLOC is a powerful, network- taken up this challenge with scanning compatible software package of the FIG 1 Remote control and multiple use of Digi- and monitoring direction finders of the tal Monitoring Direction Finder DDF0xM RAMON (radiomonitoring) system DDF (digital direction finder) family family [4] for radiolocation applica- coupled with new software. tions. DDFLOC is used with Direction Finders DDF0xM and DDF190 in com- DF units frequency operation is possible via puter-controlled direction finding and RS-232 and telephone lines, while the location of HF, VHF and UHF signals for Digital Direction Finder DDF190 is a DF connection via Ethernet or ISDN per- • radiolocation at single frequencies, unit with antennas for monitoring and mits almost unrestricted operation also • automatic monitoring of frequency test receivers covering the frequency in the scan mode. bands and frequency lists, range 20 to 3000 MHz [1]. It allows • result display on digitized map, bearings to be taken in line with ITU Digital Scanning Direction Finders • preparation of reports for location guidelines and offers a yet unrivalled DDF0xS (0.5 to 1300 MHz) are opti- results. combination of compact design, sensi- mized for fast scanning and operation tivity and accuracy. System linkup is as automatic search tools in complex Detached DF stations are controlled made via the RS-232 interface of the systems [3]. Multistage data compres- by the system controller with the aid of DF unit. sion provides the conditions required serial interfaces (RS-232) normally via for integrating the DF tools via data modems. Bearings and radiolocation While DDF190 has been designed for lines at low operating costs. results are entered online in geographi- direction finding of conventional signals cal or UTM coordinates on a digitized with a dwell time of at least 30 ms, Remote-control software map on the system controller monitor. A Digital Monitoring Direction Finders DDFREMM variety of auxiliary functions simplifies DDF0xM [2] allow also very short and result evaluation: wideband signals to be detected. De- Software DDFREMM permits the • short-term history (display of last pending on the antennas and DF con- graphical user interface (man-machine location results), verters used, a frequency range from interface or MMI) of Monitoring • position marking using icons, lines, 0.3 to 3000 MHz can be covered in Direction Finder DDF0xM to be set up areas and text elements, the fixed-frequency, search or scan detached from the direction finder and • spherical triangulation, mode. A built-in or external PC is used connected via common communication • single-station locator (option for HF for control and result processing. links (FIG 1). In addition to bearings range), System linkup is established by a two- the demodulated audio signal is trans- • postprocessing of recorded results. stage adaptive data compression for mitted. The available transmission band- each RS-232, Ethernet or ISDN inter- width is optimally used so that even at In a networked system, DDFLOC can face of the PC section. Corresponding low data rates full system operation be optionally used with other RAMON to the achievable data rate, only fixed- and almost constant detection prob- operator positions. Measurement results,

24 News from Rohde & Schwarz Number 156 (1997/IV) Application notes

Central station + DF station 1 DF station 2 On the second screen the detected Communications Communications GPS DF antenna antenna GPS DF antenna antenna signals are displayed on a digital map after processing (FIG 3). If desired, Direction Direction different bearings of a transmitter are Finder Finder DDF06S DDF06S automatically combined into plots ESMA33 ESMA33 containing all main signal parameters, eg the detected single frequencies of a EH091 EH091 hopping emitter. The movement of mobile transmitters can automatically be Monitoring DDF Position- DDF EBD92D location EBD92D receiver controller controller controller traced and stored. The system automatically recognizes known signals that are in a signal library and marks them so that new emissions can easily be FIG 2 Mobile SCANLOC system with two sta- mitters, and permits realtime display of identified. tions, each comprising Direction Finder DDF06S detected emissions on digitized maps. Franz Demmel; Günter Hinkers with VHF/UHF DF Converter ESMA33, HF DF Time synchronization is achieved by Converter EH091 and Digital Processing Unit EBD92D means of GPS receivers. FIG 2 shows a simplified system comprising two stations. Detected emissions are pre- processed at the site of the detached signal contents, location results, etc, direction finder and stored with time can of course be administered in a data stamps. These data can automatically REFERENCES base. be called by the central DF station. [1] Demmel, F.; Wille, R.: VHF-UHF Direction With the use of powerful algorithms for Finder DDF190 – Digital direction finding from 20 to 3000 MHz to ITU guidelines. With a local direction finder connected, data compression, all key information News from Rohde & Schwarz (1996) system functions are available that can be transmitted between direction No. 152, pp 30–32 cannot be used in detached direction finder and DF center at relatively nar- [2] Demmel, F.; Unselt, U.; Schmengler, E.: Digi- finders, or with restrictions only, be- row transmission bandwidths. tal Monitoring Direction Finders DDF0xM – cause of limited transmission capacity. State-of-the-art monitoring direction finding from HF to UHF. News from Rohde & In an unknown signal environment, first Results are graphically processed in Schwarz (1996) No. 150, pp 22–25 an overview of activities of interest the DF center and displayed on two [3] Bott, R.: Digital Direction Finder DDF – Mod- can be obtained in the scan mode and screens. On one screen signal activities ern scanning direction finding from 0.5 to displayed in different types of graphs. are displayed online in the form of 1300 MHz. News from Rohde & Schwarz The user may then select a signal from different diagrams: (1994) No. 146, pp 26–28 this graphical overview and locate it • signal activity versus time and fre- [4] Ehrichs, R.; Holland, C.; Klenner, G.: Radio- using the fixed-frequency mode. Another quency (waterfall), monitoring System RAMON – Customized radiomonitoring from VLF through SHF. possibility is to check a predefined list • azimuth versus frequency, News from Rohde & Schwarz (1996) of frequencies or frequency ranges for • level versus frequency (RF spectrum). No. 151, pp 19–21 activities (search) and then automatically trigger a bearing.

Location software SCANLOC

The radiomonitoring and location system SCANLOC, another powerful software package of the RAMON system family, is used with Direction Finders DDF0xS for interception and location of short, broadband and frequency-agile signals at HF, VHF and UHF. An accurately synchronized scan of all direction finders ensures high probability of acquisition and accuracy of results in the location of short-term emitters and frequency-agile trans- FIG 3 SCANLOC map display Reader service card 156/09

News from Rohde & Schwarz Number 156 (1997/IV) 25 Application notes

Planning and monitoring VHF and TV transmitters

as well as lists of transmitter frequencies Spectrum Monitoring Software ARGUS to be measured and test sites required consists of Test Receiver ESVN40 for the measurements. The monitoring (9 kHz to 2.7 GHz) for measuring field service then carries out the measure- strength, modulation, frequency offset ments with a test vehicle (FIG 2). The and reflection at VHF, RDS Decoder quality of the measurements can be DEF for decoding transmitter informa- assessed from initial evaluations tion at VHF, RDS Codec DMC01 for de- carried out on Spectrum Monitoring coding transmitter information in the TV System for Broadcast Applications band, Video Measurement System SMSB. This evaluation is based on VSA for measuring reflections in the TV selectable guidelines. These guidelines, band, and a system controller (FIG 3). which are defined by international and Antenna System FT01 covering the national bodies, stipulate the assess- frequency range from 47 to 860 MHz ment and mathematical evaluation of is used for reception. The antenna is interfering transmitters, for example. mounted with an azimuth and a The measurements may be repeated polarization rotator. The individual as required. Final evaluation of test antennas of the system are selected by results is performed by the frequency means of an antenna selector switch. planning service. FIG 1 Vehicle-mounted Spectrum Monitoring Spectrum Monitoring Software ARGUS System for Broadcast Applications SMSB The measuring equipment of onboard contains the activities to be carried out Photo 42 882/3 Spectrum Monitoring System for Broad- during a measurement run. Measure- cast Applications SMSB operating with ments may last several days and nor-

The German Post and Telecommunica- tions Office (BAPT) as well as the telecommunication organizations in other countries are responsible for frequency planning for VHF and TV transmitters together with broadcasting companies, for coordinating these transmitters with broadcasting companies at home and with relevant telecommunication organizations abroad and for monitoring the transmitter parameters. Mobile Spec- trum Monitoring System for Broadcast Applications SMSB (FIG 1) from Rohde & Schwarz is an extremely cost-effective and technically advanced solution to efficiently perform these tasks.

Normally, the organization to perform these tasks has a frequency planning service and a monitoring service. Based on certain models, the frequency planning service makes theoretical calculations regarding the coverage of FIG 2 the region by a given or planned trans- Test vehicle with Spectrum Monitoring mitter. Measurements are prepared to System for Broadcast check these calculations. To this effect, Applications SMSB different frequency ranges are defined Photo 42 882/2

26 News from Rohde & Schwarz Number 156 (1997/IV) Application notes

Compass sensor Antennas Control measurement provides in- 47 to 860 MHz formation about the state of the test system. Measurements are carried out Mast motor at fixed control test sites on transmitters of known data. They provide information about the current state of the test GPS Control Azimuth RF relay Video Compass receiver unit rotator matrix monitor equipment and thus about the quality of the measurement. Control measure-

Stereo Video RDS ments are frequency list scans with Test measure- test codec receiver ment additional evaluations. In contrast to decoder system the other types of measurement, several measurements can be carried out per RDS Teletext decoder decoder test site. The results are displayed so that the field-strength values obtained from different measurements at a test System TFT controller display site can be compared. SMSB

VHF and TV transmitter lists are required to measure and identify trans- FIG 3 Structure of Spectrum Monitoring System antenna aligned to the transmitter for mitters and programs. They provide for Broadcast Applications SMSB each channel. In this case, the sites of characteristic features of the transmitter, the transmitter and the test system have ie frequencies as well as information to be known. This type of measurement about the current or future status. Trans- mally cover several test sites. The same corresponds to a single measurement mitter lists also contain information measurements are performed at all test since only one data record is obtained about planned and project-specific sites. They are carried out automati- per channel. Each data record can be transmitters. These types of data can cally after definition of the relevant repeated with different test parameters. be entered manually or loaded into parameters. Software ARGUS supports Software ARGUS from the customer’s the following modes: frequency list Occupancy measurement is a scan database. scan, occupancy measurement, single which is defined by start and stop Jörg Pfitzner; Wolf D. Seidl measurement, channel measurement, frequency and stepwidth. It monitors polar measurement and control measure- the coverage of test sites by trans- ment. mitters.

Frequency list scan is defined by a Single measurements are used to frequency list. It is used for detecting provide an overview of the particular individual channels. Frequency list scan test-site conditions. The results are inter- can be carried out in two ways, ie with mediate results which are not stored. an aligned antenna or with a rotator. Another purpose of single measure- When it is carried out with an aligned ments is to test the settings of connected antenna, measurements are performed units in order to use them for other types for all channels at a certain azimuth of measurements. Moreover, single stepwidth over the complete angular measurement can be used as a repeat range. At every angle of measurement measurement after a frequency list scan all channels are detected by the test or occupancy measurement to identify receiver. If a measurement over 360° is transmitters and programs, for example. to be carried out at an azimuth step- In this case, the results can be stored. width of 10°, for example, 36 data records are obtained for each channel. Channel measurement is only carried Since only the data record with the out in the TV band and serves for highest field strength per channel is of measuring the in-channel offset of interest, the result with the maximum transmitters. field strength is stored. All other results are discarded. With a rotator used, Polar measurement is an azimuth- measurements are carried out with the dependent measurement at a frequency. Reader service card 156/10

News from Rohde & Schwarz Number 156 (1997/IV) 27 Software

New PropWiz software makes shortwave link prediction even more convenient

Communication via shortwave is influ- modulation methods and antenna With these new features, PropWiz enced by a variety of factors that make characteristics are taken into account. ranks top among available radio link it appear a rather changeable medium. Especially as far as antenna param- prediction programs. This is good The quality of shortwave transmission eters are concerned, PropWiz stands is substantially affected by weather con- out from competitive products. While ditions, position of sun, geographical most prediction programs take ideal ° 90 80° location and number of sunspots, to isotropic radiators as a basis for calcu- 70° ° name just a few parameters, which lations, PropWiz takes into account 60 50° sometimes make it even impossible to the antenna types actually available 40° establish a link between two points on at the transmission and reception sites. 30° the earth. Therefore, attempts have In the new PropWiz version, users δ been made worldwide for quite some can choose among a large number of 20° time to find solutions that enable reli- Rohde & Schwarz antennas (dipoles, 10° able prediction of shortwave link log periodic antennas, rod antennas, quality [1]. Propagation Wizard, ab- etc) and also define antenna types of 0° 0 2 4 6 8 10 dB breviated PropWiz, introduced by their own. Each antenna has its own Gain Rohde & Schwarz about a year ago, characteristic (gain), which is deter- is one of the most convenient and mined by the frequency and the eleva- FIG 2 Example of vertical antenna pattern powerful software programs for short- tion angle. This antenna characteristic wave radio link prediction available on is described by the vertical radiation the market [2]. pattern (FIG 2). Antenna patterns are stored under PropWiz in tabular form reason to visit Rohde & Schwarz once PropWiz not only calculates the MUF in files. An editor enables easy gen- more on the Internet home page (maximum usable frequency) but also eration of new patterns for non-R&S (http://www.rsd.de). So far, hundreds of callers on the Internet have loaded down the PropWiz software. Customers who already have a dongle for PropWiz can easily update their old software version. Anyone else interested in the new software version can operate PropWiz in the demo mode. Thomas Kneidel; Dr. Hans Waibel

REFERENCES

FIG 1 [1] Greiner, G.: Kurzwellenkommunikation: PropWiz user Historischer Überblick über die Entwicklung interface in its und Diskussion moderner Verfahren. telekom familiar form praxis, Schiele & Schön GmbH, Berlin, 23-24 (1989), 1– 2 (1990) [2] Waibel, H; Maurer, P.: PropWiz - Windows program for shortwave radio link prediction. determines the availability of a radio antennas as well as modification of News from Rohde & Schwarz (1996) No. 152, pp 46–47 link for the various times of day as existing patterns. Moreover, the new well as the appropriate frequency version also covers the new HF Data ranges. Results are output in easy-to- Modems GM2100 of the XK2000 read graphical form (FIG 1). In addi- transceiver family and runs under tion to environmental effects, device Windows 3.1, Windows 95 and parameters such as transmitting power, Windows NT. Reader service card 156/11

28 News from Rohde & Schwarz Number 156 (1997/IV) Software

Digital Direction Finder DDF190 goes RAMON

Radiomonitoring System RAMON® bearings have a spread (eg because of detects and monitors emissions in the noise or reflection), particularly in the frequency range 10 Hz to 18 GHz [1]. case of duplex operation. Thanks to the new driver for DDF190 [2], this direction finder (20 MHz to When ESMC is in the search mode, 3 GHz) can now also be integrated into DDF190 is switched off during the customized radiomonitoring systems search run and direction finding is like Digital Scanning Direction Finders restarted after ESMC has detected a DDF0xS and Digital Monitoring Direc- signal above the set threshold and has tion Finders DDF0xM. The direction stopped. While search is interrupted, FIG 2 Log window for long-term monitoring finder is used together with Compact ESMC and direction finder are con- Receiver ESMC [4] and can be operated trolled in the same way as in fixed-fre- in fixed-frequency or search mode. quency mode. Search is restarted either manually by a mouse click or auto- DDF190 is handled by the software as matically after the set hold time. Thus, a DF unit for the receiver. In the fixed- the user is also informed of the bearing frequency mode, ESMC can be tuned of a new frequency detected in a as usual. An additional window is search or when duplex operation is opened for DF control where param- monitored at different frequencies. eters can be set: DF mode, DF bandwidth, averaging time. The receiver The ESMC driver has been supplement- FIG 3 MapView digital map frequency can be directly tuned in the ed by a log window where measured DF window. Bearings are displayed data can be stored on the hard disk (graphically and numerically) as well in an MS-Excel-compatible text format RAMON permits Direction Finder as the bearing quality and relative (.CSV) (FIG 2). Data are stored cycli- DDF190 to be connected to a digital level (FIG 1). For mobile use in a cally as a function of signal level map (MapView [5]) with beam display vehicle, either north or the vehicle axis (fixed frequency), or once when the (FIG 3). This considerably enhances the can be selected as a reference for signal is above a set threshold (search). operating convenience and simplifies the bearing display by a mouse click. Statistics and diagrams can be pre- the assessment of DF scenarios. An azimuth diagram is permanently pared by evaluating the files using Claus Holland displayed in the righthand section of Excel. When ESMC is used with the window. Here the user can see DDF190, bearings are stored in sepa- REFERENCES clusters of bearings which simplifies rate columns together with the receiver [1] Ehrichs, R.; Holland, C.; Klenner, G.: Radio- an assessment of the scenario when data. monitoring System RAMON – Customized radiomonitoring from VLF through SHF. News from Rohde & Schwarz (1996) No. 151, pp 19– 21 [2] Demmel, F.; Wille, R.: VHF-UHF Direction Finder DDF190 – Digital direction finding from 20 to 3000 MHz to ITU guidelines. News from Rohde & Schwarz (1996) No. 152, pp 30–32 [3] Holland, C.; Reimann, R.: RAMON basic software for Digital Direction Finders DDF0xM and DDF0xS. News from Rohde & Schwarz (1997) No. 153, pp 30–31 [4] Klenner, G.: ESMC-RAMON – entry into computer-aided radiomonitoring. News from Rohde & Schwarz (1997) No. 155, pp 26–27 [5] Rohde & Schwarz: Technical Information FIG 1 MapView RAMON with ESMC/DDF190 windows Reader service card 156/12

News from Rohde & Schwarz Number 156 (1997/IV) 29 Refresher topic

Digital modulation and mobile radio (VII)

3.2.4 Architecture of GMSK modulator 1 0 0 0 1 1 1 0 1 0 0 -0.5 2 Before the data stream is fed to the modulator, it is differentially encoded T using the rule d(k) = a(k) ⊕ a(k – 1) where d(k) ∈ {0; 1}. Adding –0.5 and 1 1 0 0 1 0 0 1 1 1 0 then multiplying by a factor of 2 gives a sequence of bipolar delta functions δ(k) ∈{–1; +1}. The rest of the modula- D cI(t) A tion process depends on the structure of Calculation sin x/x Gaussian ϕ ϕ lowpass filter of , sin the hardware and firmware used for and cosϕ D the modulators, the only proviso being cQ(t) A that the tolerances stated in TABLE 5 1 1 -1 -1 1 -1 -1 1 1 1 -1 Oversampling must be met for bursts lasting 562 µs. FIG 21 Generating modulation signals cI(t) and cQ(t)

Max. frequency Max. phase error how complexity can be reduced drasti- resulting direction of rotation of the RF error peak/rms cally. With this approach, differential vector, it can be verified that this form –7 1 x 10 20°/ 5° encoding need not be performed as a of modulation and the modulation separate operation and the tables for produced by the original, differentially TABLE 5 Tolerances for modulated carrier ϕ ϕ calculating cos[ fil(t)] and sin[ fil(t)] encoded signal are identical (FIG 22). can be dispensed with entirely – a These parameters depend on the major improvement. To do this, the accuracy of the modulating signals original data sequence that has been 3.2.5 Demodulating MSK and GMSK signals cI(t) and cQ(t), on the frequency and converted into a bipolar signal is multi- π phase stability of the oscillator and plied by a phasor e –jk /2. The complex As equation (20) shows, MSK signals the exact orthogonality of the I and Q coefficients c(k) that result are fed to a are frequency-modulated RF signals. In carrier components. The exact solution filter with Gaussian-like characteristics. the case of GMSK signals, only the involves finding the convolution of A complex function appears at the baseband function, which is propor- δ pc(t) · hGauss(t). The (k) are interpolat- output of the filter. Its real part approxi- tional to the output frequency, is filtered. ed using a bipolar NRZ function in mates the modulation signal cI(t), while The RF signal can also be thought of a digital filter with an oversampling its imaginary part approximates the as being frequency-modulated. Con- rate of up to x16, before they are modulation signal cQ(t). From the sequently, simple frequency demod- transformed into the function cfil(t) by a further filter with Gaussian characteristics. The next part of the modulator is 1 0 1 0 1 0 -1 0 1 0 1 -jkπ ------the same as the MSK modulator that -0.5 2 e 2 D has already been described. In other cI(t) A words, the instantaneous phase is Digital filter calculated by integrating cfil(t) to D ϕ ϕ ϕ cQ(t) obtain fil(t), cos[ fil(t)] and sin[ fil(t)] 1 0 0 0 1 1 1 0 1 0 0 A are calculated and these functions are 0 1 0 -1 0 -1 0 -1 0 1 0 multiplied by the two orthogonal carrier components (FIG 21). cI(t)

t In practice, however, there is no need to follow the exact sequence of opera- cQ(t) tions that flow from the theory. As there t are a large number of mobile stations, Direction of rotation it is essential to adopt a cost-effective of RF vector approach while at the same time meet- Reconstructed differentially 1 0 0 1 0 0 1 1 1 0 encoded data sequence ing the requirements listed above. A concept developed by Philips shows FIG 22 Efficient implementation of GMSK modulator

30 News from Rohde & Schwarz Number 156 (1997/IV) Refresher topic

ulation using conventional frequency T = 1/fIF subsampling: TA = (n+1/4)T xI(2i) discriminators or an indirect approach using FM to pulse frequency modula- i IF D (-1) tion conversion would be sufficient to stage A (-1) recover the transmitted data. Never- Inter- xQ(2i) polation theless, the considerably more complex xQ(2i-1) route of coherent demodulation, de- FIG 24 scribed in chapter 2.6, is taken. There Top: demodulation cI(t) are two main reasons for this: with A/D converter. Bottom: signals cI(t) 1. Under the same transmission con- and cQ(t) recovered c (t) by IF sampling ditions, coherently demodulated RF Q ᮡ ( l sample, signals exhibit lower bit error rates Ⅵ interpolated value) than those that are not. 2. Because of the transfer function of the mobile-radio channel, the RF signal is altered in such a way that demodu- RF signal is converted to an IF and ponent samples. The delay between lating the received signals without fed to the two mixers. The frequency of the two components is equalized by equalization would in most cases lead the superheterodyne oscillator is syn- an interpolation filter. to unacceptably high error rates. How- chronized by means of a frequency-cor- Peter Hatzold ever, equalization is only possible if the rection burst transmitted at regular inter- characteristics of the radio channel vals by the base station. This oscillator REFERENCES over time are known, in other words its provides the two orthogonal signals Mäusl, R.: Digitale Modulationsverfahren. Hüthig transfer function must be continuously cos(ωt) and –sin(ωt). After passing Verlag, Heidelberg, 1988 estimated. through the mixers and lowpasses, the Proakis, J. G.: Digital Communications. McGraw Hill, New York, 1989 Schöffel, P. et al.: Architektur eines Mobilfunkge- cos␸t rätes für das Netz D. Philips Innovation (1/1991) Picken, D.: The GSM mobile-telephone network: A xI(t) Digital signal To D processor for technical features and measurement require- channel estimation, decoder IF ments. News from Rohde & Schwarz Nos. 136, channel correction stage and deriving data 137, 138 xQ(t) A most likely to be D sent Lüttich, F., Hecht, A.: Testing digital radio re- FIG 23 Frequency ceivers with Signal Generator SMHU58. News synchronization sin␸t GMSK demodulator from Rohde & Schwarz Nos. 136, 137

As described in chapter 2.6, coherent two components of the equivalent demodulation gives the complex baseband signal undergo D/A conver- envelope of the RF signal, which is also sion and are fed to a digital signal pro- modified by the radio channel. If the cessor that, from the distorted complex undistorted baseband signal is known envelope, reconstructs the sequence that as well, the transfer function of the is most likely to have been transmitted. channel can be calculated. A sequence of 26 bits, referred to as the training se- For the demodulator too there are quence and a copy of which is stored less involved solutions. FIG 24 shows in the receiver, is transmitted in the a concept that uses just one A/D middle of every burst of 156 bits. converter. The received signal that Digital modulation and mobile radio By finding the cross-correlation of the has been converted to an IF is under- Refresher topic received equivalent baseband signal sampled using a sampling period of 1 and the complex envelope that the Ts = (n + /4)T, where T is the IF period. i training sequence would generate if The samples xi are multiplied by (–1) , reception were ideal, the characteristics in other words the samples with odd of the radio channel can be estimated. indices have their signs inverted. Sam- ples with indices of the form 2i are the Reader service card 156/13 for a copy of the The block diagram of the demodulator I-component samples of the received complete refresher topic (available in English and is shown in FIG 23. After reception, the signal, those with (2i – 1) the Q-com- German)

News from Rohde & Schwarz Number 156 (1997/IV) 31 Panorama

Insertion Units URV5-Z2 and URV5-Z4 for voltage, level and power measurements up to 3 GHz

which nearly 10,000 units have been level and power indication is made at sold since their market introduction in the basic unit. 1984. Accommodated in an attractively designed plastic enclosure, their With modulated envelope or high distinguishing feature is the frequency harmonic content, the insertion units range, which has been extended from should be operated only within the 2 to 3 GHz to allow for new applica- square-law region of the RF rectifier, tions. Other features have remained which for URV5-Z2 ends at approx. essentially the same, for example the 22 mV (–20 dBm into 50 Ω) and for calibration data memory. This concept, URV5-Z4 at 220 mV (0 dB into 50 Ω). introduced by Rohde & Schwarz and In this region, the behaviour of the meanwhile state of the art, makes for insertion units is similar to that of a easy operation and high measurement thermal power meter, ie the rms voltage precision through the numeric correction or the equivalent average power is of results using calibration data sepa- measured. rately determined for each insertion unit. Thanks to the high decoupling of the Each of the new insertion units offers a rectifier from the RF connectors, inser- dynamic range of over 90 dB for spec- tion loss of URV5-Z4 is very low, ie not trally pure sinusoidal signals with an exceeding that of a line of equivalent unmodulated envelope (CW, FM, ϕM, length. URV5-Z4 is therefore truly trans- GMSK, FSK, etc). This gives a voltage parent and can be inserted into any test measurement range of 200 µV to circuit without influencing the measured New Insertion Units URV5-Z2 and URV5-Z4: 10 V (–60 dBm to +33 dBm into 50 Ω) parameters. This yields a nearly ideal versatile, compact and attractively designed for URV5-Z2, and 2 mV to 100 V voltage and power sensor which, com- Photo 43 021/1 (–40 dBm to +53 dBm into 50 Ω) for pared to conventional power sensors, URV5-Z4. The frequency range is from stands out for its exceptionally wide 9 kHz (URV5-Z2) or 100 kHz (URV5-Z4) dynamic range. Coaxial voltage measurement probes to 3 GHz. The units are made up of are among the standard accessories a short, coaxial line between the two Due to their high versatility, the insertion of RF voltmeters and power meters. RF connectors, in the middle of which units will open up a wealth of new Coming as insertion units, they are the voltage is tapped: directly with applications, continuing the success particularly versatile as they can be URV5-Z2, and via a capacitive 20 dB story of the predecessor models. connected into a test circuit without divider with URV5-Z4. If the insertion Sounds interesting? Try them out: sim- interrupting the signal flow. They can unit is match-terminated, the voltage is ply “plug and play”. thus be used for a wide variety of constant over the whole length of the Thomas Reichel applications, such as monitoring tasks line, so a fixed relationship is obtained of any kind as well as level control and between applied RF power and test terminated power measurements. voltage. In this configuration, the insertion units provide precise absolute The two new insertion units (FIG) for power and level measurements. They Voltmeters, Level and Power Meters are calibrated so that the source power URV35, URV55, URV5, NRVS and available into 50 Ω is indicated. With NRVD were developed on the basis of a poorly matched load, precise ab- the successful predecessor models* of solute-value measurements are not possible, but relative measurements can be performed and system applications * Betz, T.; Köhler, D.; Reichel, T.: RF Millivolt- implemented in which subsequent cali- meter URV5 – voltage and power measurement into the gigahertz range. News from Rohde & bration of the complete test setup takes Schwarz (1984) No. 106, pp 16 –18 place. Switchover between voltage, Reader service card 156/14

32 News from Rohde & Schwarz Number 156 (1997/IV) Panorama

From dual-mode to multimode radiocommunication tester – IS-136 standard now implemented in CMD80

Digital AMPS TDMA system (IS-136 • Error vector magnitude, a modula- This signal is fed to the receiver. The bits standard) is a mobile radio standard tion measurement specially matched demodulated in the mobile station are that has attained a degree of impor- to the modulation mode used in this compared with the known bits. This is tance in the US and other countries system. The vectorial deviation of done either by the mobile station or by almost equalling that of analog AMPS the measured signal from the ideal the controller of the mobile station. and CDMA. For this reason Rohde & signal is calculated and the magni- Schwarz has decided to support this tude of this vectorial error function User prompting and instructions given standard with its Digital Radiocom- represented as a time function (FIG). in plain text allow manual operation of munication Tester CMD80, in addition Derived error parameters are peak CMD80 without detailed knowledge of to analog AMPS and CDMA already and rms value of this time function. the individual networks. When CMD80 covered by this tester [1; 2]. The basic In addition, the measurement algo- is remotely controlled via the IEC/IEEE- design of CMD80 makes it ideal for this rithm also provides the frequency bus interface, top measurement speeds added feature: CMD80 is a compact error as well as I/Q offset and I/Q are obtained. This together with the tester covering the whole frequency imbalance. compact size of the unit is an important range from 800 to 2200 MHz. Trans- • Magnitude error; this measurement prerequisite for its effective use in a mit and receive frequencies can be is used to determine amplitude errors production environment. handled independently of each other. arising during modulation. The tester’s measurement functions are • Phase error arising during modula- Around the world, new mobile commu- based on state-of-the-art digital signal tion. nication standards are being devel- processing techniques. This allows test • Power versus time; an important oped or existing standards modified to results to be available within very short measurement in all TDMA systems. match country-specific requirements. time, which is an invaluable asset in • Adjacent-channel power; the power Offering the user convenient dual- and mass production where speed of oper- pulses occurring in the TDMA system multimode mobiles is common not only ation is a crucial factor. The use of DSP and the type of modulation used can in the US. This is why it is a great plus technology yields two more significant affect the adjacent channels, so ad- for manufacturers of radio equipment to benefits: measurement functions can jacent-channel power measurement have several mobile radiocommunica- be enhanced by means of software is of particular importance. It is tion standards combined in a tester like updates, and even totally new measure- performed in six adjacent channels CMD80, whose design also enables ment techniques (TDMA) can be adopt- altogether (three channels left and future standards to be integrated at a ed through software alone. three channels right of the user later date. channel). Thomas Maucksch When used for transmitter testing, CMD80 awaits the signal emitted When used for receiver testing, by the mobile station transmitter at a CMD80 emits a test signal at a select- particular frequency and power level able frequency, whose level can be both defined in advance. It then records chosen from a wide range. The signal REFERENCES the signal and interprets it under contains a known bit sequence that is [1] Maucksch, T.: CMD80: measurements for various aspects: suitable for bit error rate measurements. CDMA and AMPS mobiles. News from Rohde & Schwarz (1997) No. 154, pp 22–23 [2] Mittermaier, W.: Digital Radiocommunica- tion Testers CMD65 and CMD80 – Multi- band and multimode testers for mobile-radio telephones. News from Rohde & Schwarz (1997) No. 155, pp 6–8

Result of error vector magnitude measurement to IS-136 standard with Digital Radio- communication Tester CMD80 Reader service card 156/15

News from Rohde & Schwarz Number 156 (1997/IV) 33 Panorama

Optional input interface for TV Test Transmitter SFQ

With the optional input interface provided, SFQ has two different input interfaces: an asynchronous serial interface (ASI) and a synchronous parallel interface (SPI). The two interfaces meet the DVB specification and cover most of the applications. The input interface treats the two interfaces in the same way by internally transforming the serial data of the ASI into parallel form according to SPI. In the first processing step, the input data rate and packet length of the transport stream are determined and displayed for information and monitoring (FIG 2).

FIG 1 TV Test Transmitter SFQ for testing TV The MPEG2 transport stream is a con- In the next step, a device-internal output receivers Photo 42 961/1 tinuous data stream which serves for data stream is generated from the input the transport of video, audio and data data stream. The output data rate is signals. It consists of data packets with linked to the output symbol rate of SFQ. a constant length of 188 or 204 bytes For this data rate conversion, existing (for Reed-Solomon coding). Each null packets are removed from the data packet starts with a header consisting stream. The data rate thus obtained TV Test Transmitter SFQ (FIG 1) for of a sync word, a packet identification represents the minimum output data testing analog and digital TV receivers (PID) and various control bits. The rate of the module. The required output and set-top boxes as well as ADR remaining data bytes of a packet data rate is generated by adding null (Astra Digital Radio) receivers is used comprise the information to be trans- packets. The added null packets may in development and production as well mitted. This information may be part optionally contain a pseudo-random as in service and EMC test labs [1]. of a video stream, audio stream or binary sequence (PRBS), allowing bit From the MPEG2 input signal SFQ gen- table containing information about the error measurements. Data rate con- erates a signal coded and modulated transmitted programs of the transport version can of course also be switched according to DVB specification up to stream. Packets are allocated to a cer- off. In this case, only SPI is available a frequency of 3300 MHz. Channel tain program via the PID. Null packets and SFQ operates like a unit without coding and modulation are performed can be inserted to adapt the data rate an input interface (TS Parallel mode). either for cable or satellite transmission. of the transport stream to the data rate The input signal whose data rate may required by the transmission channel. If a transport stream is modified by be between 2 and 60 Mbit/s is applied These null packets do not contain any removing or adding null packets, as to SFQ via a synchronous parallel inter- information and can be recognized by described above, the relative position face. In this case, input data rate and their specific PID. of MPEG2 packets is changed since output symbol rate of the modulated signal are directly linked to each other. The conversion factor is obtained from the selected puncturing rate of channel coding and the number of bits per symbol according to the type of modulation chosen. If the output symbol rate is to be selected independent of the input data rate, optional input interface is the right solution. A synthesizer in the module generates the exact symbol FIG 2 rate even if no MPEG2 input signal is Menu for input available. interface

34 News from Rohde & Schwarz Number 156 (1997/IV) Panorama

the null packets now have a different To keep the deviation from the original REFERENCES position in the transport stream. This values to a minimum, a constant value, [1] Kretschmer, E.; Zimmermann, F.-J.: TV Test means that the program clock reference ie the minimum dwell time of a packet, Transmitter SFQ – Digital test signals for the television future. News from Rohde & (PCR) values in the transport stream are is subtracted from the corrected PCR Schwarz (1997) No. 153, pp 14 –16 no longer correct. (PCR values indicate value. The jitter added by correcting the [2] Fischbacher, M.; Weigold, H.: MPEG2 Gen- the program time at which the packets PCR value is far below the limit value erator DVG and MPEG2 Measurement De- leave a processing unit [2]). For stipulated by DVB specification. coder DVMD – Test equipment for digital TV correcting the PCR values the actual Peter Schmidt in line with MPEG2. News from Rohde & Schwarz (1996) No. 152, pp 20–23 dwell time of the packets on the input interface is added to the original value. Reader service card 156/16

ReFLEX25 and FLEX roaming in Signal Generator SME

Together with FLEX protocol option Moreover, Rohde & Schwarz has clear- (SME-B41) Signal Generator SME was ly extended the previous FLEX Protocol in the past already able to generate Option SME-B41. In its new version, standardized messages of the FLEX the FLEX protocol defines far-reaching radiopaging service and to simulate roaming characteristics for paging a FLEX base station which can be used receivers also permitting the reception as a general test signal source in of messages outside the home network. the development and production of Therefore, SME can now generate stan- pagers*. Now Rohde & Schwarz dardized roaming information in FLEX has created a new software option messages and thus allows comprehen- (SME-B43) which enables SME to sive testing of the new roaming pager generate also messages for ReFLEX25, generation. NID and SSID roaming another member of the FLEX protocol information is generated, for example, family. The FIG shows the manual and besides normal user messages, control menu of this option in which all secure messages, instructions for SSID relevant parameters for the generated subscribers, emergency resync frames, ReFLEX25 message and for the simu- filler data and simulated data of other lated base station can be varied as pager protocols can be transmitted. required. All settings are also possible Another innovation is mixing different via IEC/IEEE bus, of course. The types of messages within a cycle. parameters meet all the requirements Furthermore the timing sequence of the that may occur in practice. Some of the output information can be controlled parameters can even be set to values more precisely. These two additional Possible settings for ReFLEX25 messages in not complying with the standard in manual control mode of SME characteristics further reduce the critical order to activate special modes of a time of final testing in receiver produc- receiver, for example. tion. control messages such as SCI frame, Daniel Schröder The Frame Contents menu used to de- switchover to a bit error test mode or termine the contents of the individual emergency resync frame. For appli- message parts allows to set frames with cations beyond this, up to nine frames user messages as well as frames with with user-defined data can be processed by a PC and inserted anywhere in the ReFLEX25 message. Bit error tests with customer-specific test pattern can * Leutiger, M.; Schröder, D.: Signal Generator thus be implemented, for example, or SME for tests on ERMES, FLEX and POCSAG pagers. News from Rohde & Schwarz (1996) user messages can intentionally be No. 150, pp 38–39 corrupted. Reader service card 156/17

News from Rohde & Schwarz Number 156 (1997/IV) 35 Panorama

Rohde & Schwarz naval communications systems for joint Dutch-Spanish project

If the corresponding line is not required, its amplifier will not be driven, thus saving power, increasing reliability and reducing interference/ collocation problems. • The major part of the dissipated power is not given off in the amplifiers but in separate load resistors which are optimally cooled (eg with water). • Receivers/exciters can be operated as additional receivers via a separate receiving antenna when they are not required for transmission. • Only the power level required for a HF Broadband System XB2900 for the “Rotter- Navy and international naval projects, given link is generated in each HF dam” of Royal Netherland Navy (art impression Rohde & Schwarz won the order for the broadband power amplifier; this by courtesy of Royal Shelde Shipyard Nether- lands) Photo 43 019/1 joint-venture HF communications system increases the lifetime of the units. in 1995 against a strong field of inter- • Thanks to the fully passive configura- national competitors. Prior to this, tion of the output circuits the system HF Broadband System XB2900 was is suitable for fast data transfer and developed based on RF components also for adaptive and frequency- The increasing demand for naval com- of Transceiver Family XK2000 [1; 2] agile radiocommunication methods. munications – notably in the HF band – and in close cooperation with the • A frequency spacing of 1% is suffi- has led to the development of new experts for naval system engineering cient for operation of the individual concepts in recent years, which must of Rohde & Schwarz Hamburg and lines free from mutual interference. also take into account the limited space Rohde & Schwarz Netherlands. A func- • Continuous operation of the complete for antennas onboard ships. A compar- tioning XB2900 prototype was then system is guaranteed for a tempera- ison with other navies shows that the presented in good time to the decision ture range from –25 to +55°C. Royal Netherland Navy has a great makers of the Dutch and Spanish Navy deal of experience in the field of HF who were convinced by the following broadband systems. This experience excellent characteristics of the HF Standardized double racks form the was put to use in the design and defini- broadband system: basis of the HF broadband system. tion of the shipboard antenna system • The system consists exclusively of These racks accommodate four 1 kW when planning of the Amphibious standard components, which is an Transceivers XK2900, power manage- Transport Ship/Landing Platform Dock important aspect for onboard logis- ment unit, broadband couplers and (ATS/LPD) was started in spring 1992 tics. junction panel for cabling (FIG). The as a part of a joint Dutch-Spanish • The individual components are small output signals of the racks are com- project. Among the major tasks of the and lightweight and can thus be bined using couplers and fed to two ships are transport and landing of accommodated even where space the three-section broadband antenna and supply to crisis reaction forces as is limited. system via a triplexer. The broadband well as humanitarian relief operations • The system allows intelligent and antenna system is adapted to the spe- in times of peace. Besides a docking extremely flexible power manage- cific onboard environment, ie the ship area for landing craft the ships also ment, ie the exact number of commu- superstructure. The Royal Netherland provide accommodation facilities for nication lines needed is activated Navy has carried out preliminary meas- helicopters. with the currently required HF output urements on a brass model to optimize power. the impedance characteristics. The Based on the wealth of experience • A separate HF amplifier is assigned results were of course taken fully into gained in the field of HF naval com- to each broadband line, thus ensur- account by Rohde & Schwarz through- munications systems with the German ing optimum linearity characteristics. out the design of the system.

36 News from Rohde & Schwarz Number 156 (1997/IV) Panorama

Rohde & Schwarz not only supplies had to be made. It was first necessary February this year, the first ship was the HF radiocommunications system to ensure the cooling water supply of christened “Rotterdam” at the Dutch required for this joint project but also the HF broadband system, considering shipyard Royal Schelde in Vlissingen a complete internal and external com- that more than twenty 1 kW Trans- and is now being fitted out. The “Rotter- munications system. The future tasks to ceivers XK2900 need to be cooled suf- dam” is to be put into service at the be fulfilled by these platforms indicate a ficiently under all operating conditions. beginning of next year. The Spanish high demand for close-range communi- The power supply of the complete com- ship named “Galicia” was built at cations, which is reflected by a variety munications system was not that simple the Spanish shipyard in Ferrol and will of transmit and receive lines for VLF, either: the power offered by the local be handed over to the Spanish navy HF, VHF and UHF onboard the ship. mains distributor was not high enough in spring 1998. An intercom and a shipboard public and an additional generator had to be Norbert Linge; Robert Träger address system provide, among others, used to attain peak powers. Another internal communications. challenge was the large number of test cables and distribution boxes. Within REFERENCES To verify that this communications system only two months 4000 m of cable had [1] Buchholz, H.; Köhler, H.: HF Broadband fully complies with the characteristics to be run and fitted with connectors or System XB2900 – Custom-tailored shortwave communications. News from Rohde & stipulated by the contract prior to being wired into terminal boxes. Schwarz (1997) No. 154, pp 12–14 installed onboard the ship, Rohde & [2] Träger, R.: HF Transceivers XK2500 and Schwarz set up the racks in a hall near After a successful “rehearsal”, the XK2900 – The new members of the HF Trans- Hamburg that was specifically rented “premiere” is currently being prepared ceiver Family XK2000. News from Rohde for this joint project. To guarantee at the Dutch and Spanish shipyards & Schwarz (1997) No. 153, pp 12–13 successful acceptance testing of the with the active aid of the local Rohde system, a whole series of preparations & Schwarz representatives. End of Reader service card 156/18

Passenger telephone system Jetcall 2000 up and away

Rohde & Schwarz and its French partner senger telephone (FIG). Compared to Mors have already installed 96 of telephone systems installed so far the jointly developed terrestrial flight which are based on satellite transmis- telecommunication systems in short- sion, this service is attractive because and medium-haul aircraft of Air France. of its higher speech quality and phone After a year’s testing under commercial charges reduced by half. JetPhone, and technical aspects carried out on currently the only TFTS service provider domestic and international flights, the in Europe, expects up to 20 telephone French airline in June this year placed calls per day per aircraft. JetPhone is another order for fitting out 13 air- at an advanced stage of negotiations planes – among them Airbus A320, with Crossair, a subsidiary of Swissair, A321, A319 and Boeing 737 – as well and with Aer Lingus and Braathens. Jetcall 2000 is an extremely favourably-priced as an option for another eight aircraft. Precontract negotiations on the instal- air-to-ground-to-air passenger telephone system. The complete short- and medium-haul lation of TFTS Jetcall 2000 systems Photo 41 900/1 fleet of the Air France group will thus be are being conducted with four other equipped with Rohde & Schwarz/Mors airlines. units. Aero Leasing was the first airplane to With the Jetcall 2000A version Rohde be equipped with Jetcall 2000A. More than 180 European aircraft to & Schwarz/Mors are offering an Ekkehardt Claußen date are equipped already with the extremely lightweight and cost-efficient

TFTS (terrestrial flight telecommunica- TFTS solution for use in business, VIP Reader service card 156/19 for further information system) air-to-ground-to-air pas- and regional airplanes. A Falcon 20 of tion on TFTS

News from Rohde & Schwarz Number 156 (1997/IV) 37 Newsgrams

Monitoring Software ARGUS, pro- the SAR service of the air force was viding BAPT with a complete solution developed in close cooperation with for radiomonitoring, radiolocation representatives of the air force, and measurements in the field of government and industry, and with sound and TV broadcasting. due consideration of state-of-the-art J. Pfitzner technologies. Rohde & Schwarz as the prime contractor was entrusted with the task of translating operative requirements into technical solutions. New aeronautical radio network Rohde & Schwarz has been known with control center for for decades as a reliable partner in SAR service of German air force the implementation of radiocommu- By order of the Federal German nication projects and is cooperating Minister of Transport the German with the renowned company of Fre- armed forces established a national quentis, Vienna, in the field of voice search and rescue (SAR) service for communication switching systems. aircraft. This service, based on heli- The new system, which in its full Signing of contract for develop- R&S supplies new test vehicles copters that are always on standby, configuration will comprise 33 radio ment of test equipment for global- to Federal German Post and can also be deployed for civil tasks stations, will be ready for operation coverage dual-mode mobiles Telecommunications Office to provide support in emergency at the end of 1997. A subnetwork

In early July 1997 ICO Global A new generation of test vehicles Communications, renowned mobile- (photo) was handed over to the Ger- radio service provider with head- man Post and Telecommunications quarters in London, and Rohde & Office (BAPT) in June this year. The Schwarz signed a contract for the test vehicles are equipped with Spec- development and production of test trum Monitoring System for Broad- equipment for dual-mode mobiles, cast Applications SMSB from Rohde which in the future will enable par- & Schwarz for VHF and TV transmit- ticularly convenient communication ters (see also page 26 in this issue). worldwide via satellite and within lo- The five test vehicles are used in the cal digital networks. Most important whole of Germany to support trans- for Rohde & Schwarz in this con- mitter frequency planning and mon- tract is the section on ICO11.10 test- itoring. What is new in the imple- ing requirements (similar to GSM mentation of these government tasks 11.10), in which the methods for ex- is the fully computer-controlled inte- ecuting the test cases are described. gration of the wide variety of meas- The contract has a duration of 30 urement tasks to be performed, their months and encompasses a volume automatic evaluation and linkage to of about US$18.5 million. the central BAPT database system. situations. In the past few years, encompassing 20 transmit and re- This has become possible through a concept for setting up a new SAR ceive stations was put into operation Following the contract signing the further development of Spectrum control center and radio stations for in July. On the occasion of the offi- ceremony, Olof Lundberg, Chief cial handover of this subnetwork in Executive of ICO (in photo second Münster in the state of Westphalia, from left), said: “This represents a Hans Wagner, President and COO major milestone for ICO. Rohde & of Rohde & Schwarz, handed over Schwarz’s unrivalled expertise in test to Major General Back, head of and measurement systems for digital the rescue service center, the coat communications terminal equipment of arms of the SAR control center makes it the perfect partner for ICO. (photo above). In forging this true partnership with Rohde & Schwarz, ICO demon- An essential new feature of the aero- strates once more its commitment to nautical radio network is the linking offer high-quality and world-class of the communications system to user terminals to all our customers.” database systems which provides Dr. Wolfgang Winter, Managing access to rescue control centers, lists Director of Rohde & Schwarz UK of hospitals, airports, etc. The system (second from right), said: “The operates nonblocking throughout, growing demands for mobile com- ensuring that any radio call reaches munication require highly sophisti- its destination, which helps to save cated engineering on a worldwide human lives day-to-day. The SAR basis, which is guaranteed by Rohde control center of the air force in & Schwarz. ICO has chosen the best Münster is responsible for the whole partner to fulfil its challenging tar- of Germany except for its northern gets to introduce the next generation state of Schleswig-Holstein for which of dual-mode cellular/satellite user the German navy with headquarters terminals, which will open up a new in Glücksburg, which has its own level of communication services to radio network, is competent. the world market.” PI M. Fraebel

38 News from Rohde & Schwarz Number 156 (1997/IV) Newsgrams

symposium took place in the “Athens Optical module testing with enhanced model Hilton” hotel in April this year. A of LaserVision System large number of invited visitors from Compared with very successful ing method. With a test rate of more ministries, authorities, universities LaserVision System LV1 (see News than ten components per second, the and industry were welcomed in a from R&S No. 150), LV2 from speed corresponds to that of modern congenial atmosphere. The visitors Rohde & Schwarz (photo) features automatic mounting machines and were particularly interested in digi- additional test capabilities and allows the system to be directly used tal TV transmission and test equip- higher test speed. The system is for process control on the assembly ment as well as in GSM radio testers. particularly suitable for testing line. LaserVision System LV2 offers Lectures on theoretical aspects were SMDs whose in-circuit testing is very additional test capabilities. An im- followed by practical demonstra- limited because of the difficult adap- proved position determination pro- tions on the equipment (photo). tation involved. The main fields of vides the X-Y coordinates of SMDs application include testing of mobile and the actual angle of mounting. The visitors’ favourites were Digital communication terminals as well as Another new feature is the measure- Radio Tester CTS55 and EMI Test Re- of consumer and car electronics, ment of the height profile of the ceiver ESPC from Rohde & Schwarz where large quantities call for cost- whole DUT, allowing easy and fast as well as the new oscilloscopes from Tektronix which use digital real time and InstaVu(TM) techniques. They News from all over the world allow individual events to be detect- for hotel guests ed in full bandwidth and randomly The hotel “Am Stadtgarten” in Frei- deviating signal waveforms to be burg offers its guests a very special displayed. Digital Radio Tester CTS55 service. If they wish, they can have a which provides fast function test- room with a shortwave receiver. ing of GSM and DCS1800/1900 Rohde & Schwarz Receiver EK07 of mobiles is highly interesting for use long standing has recently been re- in Greece since the third Greek GSM placed by a modern EK896 (photo). network is being installed by the PTT Frequencies covering the guests’ in line with the GSM1800 standard. home regions can be prepro- Tektronix’s pocket-size PAL Signal grammed. Thanks to the clear Generator TSG95, which for exam- and simple user interface of EK896, ple can generate 20 of the most effective and fast testing. Compared checking even of complex structures. the guests can carry out their own important test patterns, met also with other common optical test The new array test software enables settings without special knowledge. with great approval. systems, LaserVision features a simple duplication of similar tests, so This service is appreciated and used unique combination of image pro- that a lot of time can be saved in pro- in particular by guests from over- The exhibition in Athens was a great cessing and laser height measure- gram generation in particular when seas. Besides a long-wire antenna success within the framework of the ment and provides an extraordi- testing frequently occurring compo- Active Rod Antenna HE011 ensures sales cooperation between Rohde & narily high level of fault detection, nents. LaserVision System LV2 can optimum reception quality. Schwarz and Tektronix. ultra-low pseudo-fault rate and an be used as a stand-alone test set or R. Mayerhofer B. Mohacsy excellent price-performance ratio in combination with a conventional thanks to low investment costs. in-circuit or functional test system from the TSAx or TSUx families. PI As compared with LV1, the measurement speed has been considerably increased by a new image process- Reader service card 156/20

ISO 9002 certificate for Rohde & Schwarz Canada Inc.

In June 1997 yet another Rohde & Schwarz sales agency was granted certification of its quality management system in line with the ISO 9000 standards. Rohde & Schwarz Canada Inc. received confirmation that it meets the requirements of ISO 9002-1994 (photo). This certification, which includes both sales and service, not only confirms the high quality standard of Rohde & Schwarz products, but is also an evidence of Rohde & Schwarz’s efforts to Joint exhibition implement worldwide quality assu- by Rohde & Schwarz rance as a management method. and Tektronix in Athens H. Penning It is almost a tradition since this is the third time that the joint Rohde & Schwarz-Tektronix exhibition with

News from Rohde & Schwarz Number 156 (1997/IV) 39 Information in print

Power Reflection Meter NRT (200 kHz to 4 GHz; Our services at your service “Rohde & Schwarz 0.3 mW to 2 kW) measures peak and burst power Cologne Plant helps you all along the line” is the as well as crest factor and simultaneously displays promise of the R&S service center. For more details, power and reflection digitally and as a bargraph; have a look at the new brochure. new sensors (for direct connection to PC): NRT-Z43 (from 400 MHz) 7 mW to 30 W (peak 75 W), Info PD 757.3386.21 enter 156/28 NRT-Z44 (from 200 MHz) 30 mW to 120 W (peak 300 W), compatible with main digital modulation Creativity shaping new worlds (Who we are...) standards (average power values independent and Competence for a communicative world of modulation mode); Sensors NAP-Z.. can be con- (...and what we do) are the titles of a brochure in Security Management System USEIT nected via option; built-in battery charger. two parts, in which Rohde & Schwarz presents itself as top in test & communications, explains Data sheet PD 757.2396.21 enter 156/21 its quality- and customer-oriented philosophy and describes its business fields and product groups. Security Management System USEIT from SIT (Gesellschaft für Systeme der Informationstechnik Info PD 757.3557.21 enter 156/29 mbH) detects and automatically or manually eliminates weak spots of UNIX operating systems on single PCs or in networks. (Data sheet only available in German for the time being).

Data sheet PD 757.3505.11 enter 156/22 Four-Line V-Network ENV4200 (150 kHz to 300 MHz) with 50 µH||50 Ω impedance is an Vector Signal Generator SMIQ (model 02 for 0.3 artificial hand and designed for 4 x 200 A con- to 2.2 GHz, model 03 for up to 3.3 GHz) allows – tinuous current. depending on the type of application – digital, vector and classic modulation modes (digital Data sheet PD 757.3428.21 enter 156/25 standards at a keystroke) with short setting times and high spectral purity as well as for the first time Tracking Generators FSE-B8 to FSE-B11 (-B8/ 6-path and 12-path fading simulation; level range -B9: 9 kHz to 3.5 GHz, -B10/-B11: up to 7 GHz) –140 to +13 dBm, internal data generator, broad- enhance Spectrum Analyzers FSE for selective band I/Q modulator, broadband FM and AM, scalar network analysis; attenuation measurement Creativity shaping new worlds frequency hopping, RF/AF/level sweep; economy to typ. 120 dB, output level optionally to –90 dBm, Who we are … models for use in production. -B9/-B11 with I/Q modulator.

Data sheet PD 757.2438.21 enter 156/23 Data sheet PD 757.3434.21 enter 156/26

Standard Signals at the Touch of a Button This ACCESSNET® Trunked radio for professional poster (DIN A1 format) shows settable parameters users is presented by R&S Bick Mobilfunk in of digital communication systems covered by this brochure: comprising everything from design Vector Signal Generator SMIQ. support through to service after commissioning.

Poster PD 757.3463.21 enter 156/24 Info PD 757.3170.21 enter 156/27 New application notes

Group and Phase Delay Measurements with Vector Network Analyzer ZVR Appl. 1EZ35_0E enter 156/30 Standard Signals at the Touch of a Button. File Transfer between Analyzers FSE or ZVR and PC using MS-DOS Interlink Appl. 1EZ34_0E enter 156/31

Accessing Measurement Data and Controlling the Vector Network Analyzer via DDE Appl. 1EZ33_0E enter 156/32

Collection of Setups for Measurements with Audio Analyzers UPL and UPD Appl. 1GA36_1E enter 156/33

Automatic Run of Rec. 11.10 Testcases (Remote Control of MS Function) Appl. 1CMAN30E enter 156/34

BER Measurement with 50 kHz Frequency Offset and Blocking 2 Measurement Appl. 1CM29_1E enter 156/35

Schz

40 News from Rohde & Schwarz Number 156 (1997/IV) Press comments

John Watkinson, editor of the US journal TV Tech- Go or NoGo nology & Production, chose the photo on the left for the April issue as an eyecatcher for his report The 16/97 edition of Funkschau deals with the on digital video broadcasting. He described testing of GSM telephones and presents among among others test and measurement require- others Digital Radio Tester CTS55: ments in this field. The photo shows MPEG2 Generator DVG and MPEG2 Measurement CTS55 too offers automatic test functions. The Decoder DVMD which fully comply with MPEG2 quick test allows a very fast check of the most and DVB specifications. important functions with a go/nogo message. A second autotest version gives more detailed results on three RF channels but it takes a little more time. These functions enable the mobile-phone dealer to prove competence and carry out reliable diagnosis in presence of the customer. Operating CTS55 with the autotest routines does not require technical expertise. The graphics on the TFT display afford ... and once again DVB easy and fatigueless work over a long period of Around-the-clock in time. Japanese Dr. Jürgen Lauterjung, head of the T& M ad-hoc group in the Technical Module of DVB and In its 4/97 edition, the radio journal TV Technol- responsible for new technologies and strategic Solution provider with ogy & Production describes the Japanese broad- cooperations at Rohde & Schwarz, gives an basket of products caster NHK’s preparations for setting up round- overview of the state of the art in the leading ar- the-clock operation, the support given by Rohde ticle on DVB in the television, film and electronic The journal Elektronik Produktion & Prüftechnik & Schwarz for this project and the use of TV Mon- media journal FKT (7/97). He moreover refers to EPP (No. 6/97) interviewed Klaus Kundinger, itoring and Test System TS6100 for monitoring the an article by R&S employee Michael Fischbacher manager for production T& M equipment and programs: in the same issue on the subject of testing the systems, on the subject of in-production testing realtime characteristics of coders and distribution at R&S: Up to now NHK has been broadcasting up to 18 networks for digital TV networks: hours a day which left a few hours free for mainte- The different sections of our T&M division supply nance work to be carried out on the transmitters. Digital video broadcasting is now here to stay irre- a large proportion of their instruments for use in NHK intends to transmit 24 hours a day as from spective of what one thinks of it. We will probably production, in particular for testing mobile com- January 1998. This requires a new maintenance look back on 1996 and 1997 as the beginning of munication devices and automobile electronics. philosophy. To this end NHK turned to Rohde & this revolutionary technique. As a rule in such The close integration of these sections will continue Schwarz for support. Rohde & Schwarz has been cases, the first onsets are not that revolutionary at to increase. Our cooperation with Tektronix has supplying TV transmitters and test equipment for all. Market penetration, ie reaching the customer, is enabled us to have a respectable presence in US 50 years. The company has now developed a new as fast or slow as with other high-quality consumer mobile-telephone production plants. ... Production concept for its TV monitoring systems and plans goods. But those who have intensively been en- test technology at Rohde & Schwarz is on the way to install a pilot system at NHK. With this system gaged in DVB for the past three or four years can’t to becoming a strategic field of activity, creating failures can be predicted before they occur (active help thinking that the breakthrough to success will optimum solutions in long-term partnership with instead of passive maintenance). soon be made if it has not happened already. customers.

The clear favourite on the covers of the international journals Microwaves & RF (5/97), EPN Asia (6/97) and Communications Products (3/97) was Vector Signal Generator SMIQ which represents a new generation of signal generators from Rohde & Schwarz with digital modulation capability. It offers high-quality digital modulation based on precision I/Q modulation, short measurement times through fast synthesis and a large dynamic range thanks to its high spectral purity.

News from Rohde & Schwarz Number 156 (1997/IV) 41 Final article

D-channel filter – essential contribution to increased security of ISDN telecommunication systems

By order of the German Information for S2M. B channels are not affected large personnel resources to reach their Security Agency (BSI), the Rohde & either. The D-channel filter is able to objectives. These are only a few exam- Schwarz subsidiary SIT, Gesellschaft protect telecommunication systems with ples to demonstrate that the emergence für Systeme der Informationstechnik more than 10,000 subscribers. of digital technologies has brought mbH, Berlin, is developing a device new threats for IT security. If such to increase the security of ISDN (inte- What is such a filter good for, or threats cannot be avoided, protective grated services digital network) tele- ISDN interpreted differently: is such a communication systems. This device device needed? Any subscriber having performs filtering of the D channel changed from the good old analog which is used for ISDN control. telephone to digital ISDN surely would

not like to do without the advantages Administration independent The primary protection afforded by of the integrated services network, of telecommunication system the D-channel filter is the prevention of and this not only because of the higher unauthorized access to services and dialling and transmission speed. For performance features, the aversion of instance, telephone traffic, digital data deliberate misdirection of information transfer, fax transmission and other ser- and the possibility of detecting and pre- vices with a multitude of features can venting intrusions within the network now be handled via the same telecom- Inspector performing and from the outside. The filter also munication lines. It is convenient to take independent check prevents concealed information transfer one’s own extension number into the conference room or to route calls to any other telephone extension. Who has FIG 2 Separation of administrator and inspector not yet made use of the multiparty service or the handsfree facility? Not Exchange Telecom to speak of system administration. The connection system service technician need not come to the measures have to be found to reduce site anymore, he simply dials himself the risk to an acceptable minimum. The S0/S2M PCB ISDN ISDN Transparent B channel into the network from any point outside D-channel filter is an effective means for card card the system and makes all the settings this purpose. requested by the network subscriber. D-channel data Basically, the D-channel filter is an

Serial link However, what happens if the call ISDN firewall. A survey of the market Administration/ CPU inspection transfer function is used to talk to auntie has shown that there is no comparable in Australia every day free of charge product worldwide. This has also been (for the person calling)? What harm confirmed by the great number of cus- FIG 1 Principle of D-channel filter can be done when the telephone’s tomer queries at CeBIT 97. The design handsfree microphone is activated by of this filter is as follows: all (incoming an outsider just at the moment when and outgoing) information on the D strategic decisions are being made in channel is separated from the user data in the D channel for any purpose what- the very room or last details of an offer in the B channels by means of two

soever. It responds to any intrusion by discussed? Can a user of a telecom- ISDN interface cards (1 or 3 x S0 or

detecting the attempt, preparing a munication system be sure to know the 1 x S2M), which are accommodated on comprehensive report and clearing exact configuration of his system or not one PCB, and then forwarded to a pro- down the link. All D-channel packets to make mistakes in system handling? cessor board (FIG 1). The actual filter not infringing the defined filter con- What about attempts to intrude into the software is installed on the processor. ditions are through-connected to their company-internal telecommunication Filtering is performed according to the destination. The filter supports the system for the purpose of industrial following basic principle: all services high transmission capacity of the ISDN espionage? It is hardly a secret that in- and performance features that are not channels, ie the D-channel capacity of telligence services both in the East and explicitly activated for a specific exten-

16 kbit/s for the S0 bus and 64 kbit/s West resort to every means and utilize sion number or group of extensions are

42 News from Rohde & Schwarz Number 156 (1997/IV) Final article

barred. Any unauthorized attempt to algorithms. Any attempt to violate this D-channel D-channel use barred services and features is met mechanism is recorded and prevented filter filter Exchange Exchange by the filter with a link cleardown. after a selectable number of unsuccess- connection connection S0/S2M S0/S2M ful attempts. Highly security-relevant Inspection An administrator and an inspector events are signalled by an optical and are responsible for configuring and acoustic alarm. Further cryptographic S0/S2M adapting the filter to the telecommu- functions guarantee the integrity of pro- Telecom Telecom nication system to be protected and grams and filter conditions. system system S /S S /S for carrying out performance checks 0 2M 0 2M

(FIG 2). They can access the filter via a To protect telecommunication systems Administration D-channel commercial PC. Complex functions are against manipulations via PSTN or filter Exchange available to the administrator; they can private networks, the D-channel filter connection S0/S2M be handled via a familiar graphical can be connected to any S0 or S2M Telecom system user interface (Windows 95, Windows interface of a single or networked NT). Internal filter conditions can be set telecommunication system (FIGs 3 FIG 4 Configuration of networked systems via easy-to-understand menus. A differ- and 4). Each filter can serve one or

ence is made between protocol-specific three S0 interfaces simultaneously, for

and subscriber-specific filter conditions. S2M one filter is provided per interface. Protocol-specific conditions ensure trans- Thus practically all main applications Coordination in the Federal German mission in the D channel conformal to can be covered. Administration. A project-accompany- 1TR6 or DSS-1 ISDN protocol. They ing evaluation by the German BSI sets also prevent or detect unauthorized As the D-channel filter is an external high quality standards reflected, access attempts via protocol elements. unit, it can easily be integrated into ex- among other things, by the fact that The subscriber-specific filter conditions isting systems. No modifications have level E4 of ITSEC criteria has been assign authorized services and perfor- to be made to the system when the filter stipulated for software development. mance features to the extension num- is installed. As a result, the filter can be Hardware and software are developed bers. Up to 256 different subscriber easily replaced. Since the D-channel by SIT, the device itself is produced by profiles are configurable. filter is completely system-independent, R&S Messgerätebau Memmingen. the make of the system is of no impor- Another essential function of the D- tance. The special design of the filter All in all, the D-channel filter provides channel filter is the recording of any reliably prevents any attempt to ma- effective protection against existing violation of filter conditions and of all nipulate the system electrically from the and future threats to ISDN telecommu- security-relevant events in a report network via the ISDN system connector. nication systems – an indispensable which is stored in a nonvolatile memo- Management of the D-channel filter in factor for the security of digital tele- ry. Only the inspector is authorized to general does not require any special communication systems now. view, copy and clear the report data. knowledge. The D-channel filter is note- Günter Hornauer Access of the administrator/inspector worthy for its great flexibility. New filter to the filter is protected by a strict conditions can be set without any tech- authentication using cryptographic nical modifications being required. This, in conjunction with the protocol functions, allows quick reaction regarding adaptation to new, presently un-

S S known attacks. Thanks to the modular 0 0 Telecom system 1 design, the software can effectively be D-channel filter adapted to other ISDN protocols or

S S protocol versions. The cryptographic 2M 2M Telecom system 2 techniques and algorithms used for Network access D-channel filter authenticating and safeguarding the program integrity can be tailored to customer requirements.

The filter is being developed according Administration/inspection processor to structured development methods in line with the procedures of the Central FIG 3 Configuration of individual systems Office for Information Technology Reader service card 156/36

News from Rohde & Schwarz Number 156 (1997/IV) 43 Visit us on Internet under www.rsd.de · B42622 21 . 2980 . 7 ) · PD 75 V I / 7 99 1 ( 6 5 1 News from Rohde & Schwarz

ROHDE& SCHWARZ GmbH & Co. KG · Mühldorfstraße 15 · D-81671 München P. O. B. 8014 69 · D-81614 München · Tel. (+49 89) 41 29-0 · Fax (+49 89) 41 29-21 64