Rohde and Schwarz FSM Vintage Spectrum Analyzer

The Rohde & Schwarz FSM series is a family of spectrum analyzers and measuring receivers engineered for precise signal analysis, calibration, and complex measurement tasks. These instruments combine full spectrum analyzer functionality with integrated noise parameter measurement, modulation analysis, and power meter capabilities - delivering accuracy and versatility across RF and microwave applications. The FSM series excels at harmonics and phase noise characterization, noise factor determination on complex transistors, AM/FM/φM demodulation, and level calibration from +30 dBm to –140 dBm.

With resolution bandwidths from 1 Hz to 10 MHz (expandable to 40 MHz on select models), low displayed average noise levels reaching typ. –159 dBm (1 Hz) at 2 GHz, and modulation measurement uncertainty under 1%, the FSM provides the sensitivity and stability required for demanding test environments.

Technical Specifications

• Frequency Range: 20 Hz to 50 GHz (higher with external mixers)


• Resolution Bandwidth: 1 Hz to 10 MHz standard; up to 40 MHz on specific models


• Analysis Bandwidth: Up to 80 MHz (digital modulation, pulse analysis, VOR/ILS)


• Noise Measurement: Up to 26.5 GHz


• Phase Noise: Typ. –163 dBc/Hz at 10 kHz offset (1 GHz); cross-correlation analysis available


• Displayed Average Noise Level (DANL): Typ. –159 dBm (1 Hz) at 2 GHz without preamplifier


• Level Measurement Range: +30 dBm to –140 dBm or –152 dBm to +30 dBm (model-dependent)


• Modulation Accuracy: Modulation depth, frequency deviation, and phase deviation < 1% measurement uncertainty

Key Features

• Full spectrum analyzer with harmonics and phase noise analysis


• Integrated modulation analyzer for AM, FM, and φM demodulation


• Audio parameter measurement on demodulated signals or external input


• High-accuracy level calibration functionality


• Optional YIG preselection filter for image frequency rejection into microwave range

Compatibility & Integration

• Direct connection support for R&S® NRP power sensors


• Operates as precision power meter when integrated with compatible sensors