R&S®FMx Modulation Analyzer Family

The R&S^®FMAx modulation analyzers combine the functionalities of several measuring instruments in a single box (RF counter, power meter, voltmeter, audio analyzer, distortion meter, FM stereo decoder). The R&S^®FMAx modulation analyzers are suitable for measurements in the field of broadcasting (e.g. on AM and FM transmitters) and radiotelephony as well as in the calibration of signal generators.

The traditional analog techniques of amplitude, frequency and phase modulation retain their important position in all branches of communication despite the increasing use of digital modulation. The concept of the FMx family - modulation analysis for today's requirements - calls for measurement performance weIl beyond that of conventional modulation meters. The predecessor FAM from Rohde&Schwarz was a step in the right direction. Through the innovative FMx family with its range of application-specific models, this development has reached a new peak. The goals of this new design were:

• improved accuracy of all measurements
• higher measurement rates
• improved processing and presentation of the results
• optimization of the model range from the application point of view and
• retention of the basic concepts of the predecessor family FAM.

A standardized interface (the IEEE-488 bus) for applications in automatic test systems was just as important as a weIl-defined family of instruments for applications in stationary and mobile radiocommunication, in sound and TV broadcasting and in many navigation systems. Measurements on FM stereo signals are a major area of interest. Beyond the classic parameters such as modulation depth, deviation and carrier frequency, comprehensive analysis of the interfering modulation and the baseband source signal is provided for. Among the many other tests catered for are precise measurements of the carrier power and the transient behaviour of the RF carrier.

FMA combines the functions of several measuring instruments all in one unit. It allows fast and accurate analysis of all parameters of modulated signals. Thanks to its versatility, it can also be used as an RF counter, power meter, voltmeter, psophometer, distortion meter, audiogenerator and as an FM stereo decoder. FMA is suitable for measurements in the field of broadcasting (eg on AM and FM transmitters) as well as radio-telephony and in the calibration of signal generators. It can be upgraded for many other measurement tasks.

FMAB has been especially designed for the analysis of FM stereo broadcast signals. Its measurement tasks include comprehensive analysis of VHF transmitters, channel transposers and VHF/baseband converters. The built-in stereo decoder with all its analysis functions can be separately used via the rear-panel input so that measurements on FM receivers and stereo coders are also possible.

FMAS combines the characteristics of a universal modulation analyzer with those of an FM stereo/TV dual-sound receiver:

• RF/IF selection for 5 to 1000 MHz can be switched on when required
• Selective audio analyzer

• AM, FM, PM demodulation
• Fast, automatic frequency adjustment by direct frequency measurement
• Low-noise synthesizer with high frequency resolution
• Separate +PK and -PK detectors with extremely short response time
• True RMS detector
• Extremely high accuracy
• High-precision power measurement (typ. error of FMA <0.5 dB, even smaller for FMB)

• Excellent static and dynamic selectivity and high sensitivity for direct measurements at the antenna
• Excellent transmission quality
• High overload capability to interfering signals
• Selective RF level measurement
• Low distortion due to phase-linear IF filters

• Two independent frequency counters for simultaneous RF and AF frequency measurements
• All measurement times can be adapted to the specific measurement problem, eg lowest measurement frequency or required counter resolution
• Measurement functions that are not required can be switched off
• FM demodulator with high band-width for analysis of digital modulators (eg mobile radio)

• Menu-guided operation with softkeys
• Nonvolatile storage of up to 20 complete instrument setups
• Three displays for simultaneous readout of measurement results and indication of all important instrument settings
• Quasi-analog indication of high resolution with absolute or selective as well as MIN-MAX display
• IEC/IEEE-bus remote control to IEEE 488.2