Product brochure Version 02.00 July 2004 Vector Signal Analyzer ¸FSQ-K70 Universal demodulation, analysis and documentation of digital radio signals ◆ For all major mobile radio communica- ◆ For all common digital modulation ◆ Optimum representation of results: tion standards: modes: – In-phase and quadrature signals –GSM & EDGE – BPSK, QPSK, OQPSK versus time –WCDMA-QPSK – π/4 DQPSK – Magnitude and phase versus time – cdma2000-QPSK – 8PSK, D8PSK, 3π/8 8PSK –Eye diagram – Bluetooth® –(G)MSK – Vector diagram –TETRA –2, 4, (G)FSK – Constellation diagram –PDC – 16, 32, 64, 128, 256 (D)QAM – Table with modulation errors –PHS – 8VSB – Demodulated bit stream –DECT ◆ 25 MHz symbol rate expandable up to – Statistical evaluation of modula- –NADC 81.6 MHz tion parameters ◆ 28 MHz I/Q demodulation bandwidth – Spectral evaluation expandable up to 120 MHz – Amplifier distortion measurements Universal analysis of digital Fit for future standards Multiple test functions radio signals integrated in one unit The option ¸FSQ-B72 allows the The vector signal analyzer option standard demodulation bandwidth of The Signal Analyzers ¸FSQ in con- upgrades the high-quality Signal 28 MHz to be expanded to 60 MHz for junction with the option ¸FSQ-K70 Analyzers ¸FSQ, adding universal frequencies below 3.6 GHz and above replace several individual instruments: demodulation and analysis capability 120 MHz. down to bit stream level for digital radio ◆ High-grade spectrum analyzer signals. The option supports all common ◆ Vector demodulator mobile radio communications standards. Efficient in production ◆ Constellation analyzer The high measurement speed of Measurement and analysis of 60 sweeps/s in the analyzer mode and Principle of vector signal digital modulation signals typically 20 measurements/s using the analysis vector signal analyzer function is ideal for You want to measure and analyze digi- applications in production. The high flexi- The IF signal is digitized by means of a tally modulated signals? This can easily bility allows multistandard test systems fast A/D converter, allowing purely digital be done in the analog baseband or at the to be configured for easy adaptation to processing of all subsequent analysis RF up to 40 GHz with the vector signal varying production requirements. steps, thus making them practically error- analyzer option in the ¸FSQ. free and providing high long-term and temperature stability. After A/D conver- In addition to performing standard Any mobile radio standard at a sion, the signal is digitally mixed into the measurements such as determination keystroke baseband and split into a real and an of modulation accuracy, carrier leakage imaginary component. The complete or I/Q imbalance, you can also study the The high flexibility offered by the analyzer signal information is thus available for information statistics of these parameters is by no means at the price of complicated further analysis. such as the standard deviation of carrier operations: all major digital modulation frequency error calculated over 10 mea- standards can be activated at a key- The signal is demodulated down to bit surements. stroke. The instrument is then completely level by a DSP. From the data stream thus configured for measurements in line with obtained, an ideal signal is calculated. Since the ¸FSQ-K70 can analyze the activated standard. The correspond- This reference signal is compared with digital signals, it is an ideal tool for use in ing synchronization sequences are of the test signal. The resulting difference development and production. course offered along with the standard. signal contains all modulation errors (see block diagram). Versatile in the lab BLUETOOTH is a trademark owned by Bluetooth SIG, Inc., USA and licensed to Rohde&Schwarz You may want to develop future or company standards, use unconventional formats or modify synchronization sequences. In all these cases, the ¸FSQ with the option ¸FSQ-K70 will support you by providing user-selectable bit and symbol rates, filters, modulation schemes and synchronization sequences. You can even generate and store your own generic standards, save the settings and recall them at any time. List of standards 2 Vector Signal Analyzer ¸FSQ-K70 The ¸FSQ features a newly devel- Visualizing amplifier influence Searching for rare events oped digital back end that benefits from on your signal the progress in ADC and ASIC develop- By activating the multiburst capability ment. Time-consuming evaluation algo- By analyzing the difference between the you can fill the 16 Msamples of memory rithms can be implemented directly in the reference signal and the signal under with continuous data and then search hardware – a prerequisite for fast test, the analyzer can display the distribu- through the buffer to locate specific measurement and high accuracy. tion of the amplitude and phase error as events. a probability density function. ◆ 81.6 MHz A/D converter If you have a burst signal with sporadic – Optional second converter for Furthermore, the phase and amplitude disturbances, all you need to do is to cap- baseband inputs errors can be analyzed with respect to ture the signal and then step through the – Optional 326.4 MHz A/D converter, signal amplitude. The results can reveal bursts one by one to find the distorted SFDR >58 dB the cause of modulation errors and help burst. You can then use all the tools of the ◆ Digital hardware resampler to match finding the optimum operating point for ¸FSQ-K70 to locate the origin of the the sampling rate to a multiple of the the amplifier. disturbance. symbol rate ◆ Sampling rate from 10 kHz to 326.4 MHz adaptable to the modula- tion rate ◆ SFDR >80 dBfs ◆ Digital downconversion to baseband with high output bandwidth (120 MHz referred to RF) Intermodulation distortion of I/Q data: a distor- tion-free transmission range is particularly important for amplifier measurements; the illus- tration above shows the intermodulation charac- teristics of the I/Q data of a two-tone signal. A 404 MHz BP 60/ 120 MHz D ¸FSQ-B72 326.4 MHz L.O. A Iin I memory In-phase D 16 Msample Qin f = 81.6 MHz Equa- Quadrature S lizer Resampler Decimation IF filter 0 11 Processor cos 0.5 to 1 2 to 2 A NCO 25 MHz 25 MHz D sin 300 kHz, 500 MHz Q memory 1 MHz, 2 MHz 16 Msample 3 MHz, 5 MHz 10 MHz, 20 MHz fS = 81.6 MHz Sampling rate Trigger 10 kHz to 81.6 MHz Block diagram of vector signal analysis section in the ¸FSQ Vector Signal Analyzer ¸FSQ-K70 3 Applications This not only allows established stan- Modulation error measurements on dards to be measured with high preci- EDGE signals (2) Measurements on parts of signals (1) sion, but also modified settings in the The upper screen (A) shows the EVM To perform these measurements on case of new developments. Further versus time of an EDGE signal; the lower TDMA systems such as EDGE in line with trigger modes are: screen provides a summary of relevant standards, a time reference must be errors measured over a burst signal and established from synchronization ◆ External several statistical parameters calculated sequences to pre- or midamble. This is ◆ Burst over 10 bursts. done in the PATTERN SEARCH mode, in ◆ IF power which the analyzer triggers on preset or user-defined synchronization sequences. Picture 1 shows an example where the modulation quality is measured only on the training sequence of an EDGE signal. 1 2 3 4 Vector Signal Analyzer ¸FSQ-K70 Modulation accuracy measurements The SYMBOL TABLE/MODULATION Convenient analysis with vector on WCDMA mobile phones (3 and 4) ACCURACY lists the demodulated bits diagram (5) The low inherent EVM of <0.6% (rms) of and the errors found. The bit sequences The vector diagram enables convenient the option ¸FSQ-K70 substantially and the errors can be read via the fast analysis of the degradation of modulation reduces uncertainty. Tolerances, e.g. an IEC/IEEE bus or 100 Mbit LAN connection accuracy caused, for example, by nonlin- rms EVM error of 17.5% for WCDMA, can of the analyzer. earities, phase noise or amplitude-depen- thus be allowed practically completely for dent phase response of amplifiers, con- the DUT, thus widening the DUT toler- The constellation diagram of the QPSK verters, etc. The upper screen (A) shows ance margin. signal and the probability distribution of the complete constellation diagram, the the amplitudes are shown below. lower screen (B) the probability distribu- tion of the error vector magnitude (EVM). 4 5 Vector Signal Analyzer ¸FSQ-K70 5 AM/ϕM and AM/AM distortion exam- WLAN IEEE 802.11b constellation ple with a 16 QAM signal (6 and 7) diagram (8) Picture 6 shows the constellation dia- Signals where the modulation format gram where the outer constellation changes the signal quality can be ana- points are drawn to the center of the lyzed with the ¸FSQ-K70. The con- diagram as a result of the amplifier com- stellation diagram in the upper half of the pression. Picture 7 shows the AM/AM display is calculated from the QPSK part and AM/ϕM conversion curve of the of an IEEE 802.11b signal marked with the same signal. red display lines. Due to the Gaussian pulse shaping filter used by the transmit- ter, the signal is not intersymbol-interfer- ence-free and the symbol points are not single points but are distributed in a square. 6 7 8 6 Vector Signal Analyzer ¸FSQ-K70 DVB-S constellation diagram Spectral evaluation of measurement (9 and 10) results (11) The MAPWIZ tool that is available on the The spectrum of the error vector magni- Rohde&Schwarz website for download tude of an EDGE signal has clear peaks. free of charge allows the mapping of the These peaks indicate that an interferer DVB-S signal to be created.