The Rohde & Schwarz FMB is a precision modulation analyzer engineered for fast, high-accuracy analysis of modulated signals across broadcast, radiotelephony, and calibration applications. Beyond modulation analysis, it functions as an RF counter, power meter, voltmeter, psophometer, and distortion meter—making it ideal for development and validation of oscillators, transmitters, transposers, and receivers.
Technical Specifications
Frequency Coverage
• RF frequency range: 50 kHz to 5.2 GHz
• RF frequency readout: 10-digit display
• AF frequency readout: 5-digit display
Modulation & Demodulation
• AM, FM, and phase modulation measurements across wide modulation frequency ranges
• FM demodulator bandwidth: 330 kHz with deviation measurement capability to 700 kHz
• Low inherent spurious modulation
Power & Voltage Measurement
• Power measurement error: < 0.5 dB typical, < 0.3 dB guaranteed
• Maximum input voltage: 25 V DC + peak
• AC/DC voltage measurement capability
Signal Quality Analysis
• FM stereo S/N ratio: typically 78 dB at carrier frequencies to 170 MHz
• Distortion measurement (optional): 0.005% minimum in 10 Hz to 100 kHz range
RF Input
• Impedance: 50 Ω
• Connector: N type
• VSWR: < 1.4 with 10 dB attenuation
• Overload protection: up to 5 W (15 V RMS)
– Key Features
• Universal auto-sensing power input
• Psophometric weighting filters standard; optional CCIR and CCITT filters
• IEEE 488 interface for peripheral device integration
• Expandable modular architecture with distortion/SINAD, stereo decoder, AM/FM calibrator, phase noise analysis, and reference oscillator options
• Optional 5.2 GHz frequency extension module available
– Typical Applications
• FM broadcast transmitter characterization and S/N ratio verification
• Signal generator calibration and validation
• Transmitter and receiver development
• Deviation and modulation index measurements
– Compatibility & Integration
The FMB integrates with Rohde & Schwarz modulation analyzer family (FMA, FMAB) and process controllers for automated monitoring and peak deviation measurement.
