Rohde & Schwarz FSQ3 20Hz – 3.6GHz Spectrum Analyzer

The Rohde & Schwarz FSQ3 is a dual-instrument spectrum and signal analyzer delivering high dynamic range measurement across 20 Hz to 3.6 GHz. It combines broadband frequency coverage with advanced demodulation capabilities up to 120 MHz, enabling precise characterization of complex modern wireless signals. The instrument achieves DANL of typically -158 dBm (1 Hz RBW) with total level uncertainty of 0.3 dB across its full frequency range.

Third-order intercept reaches +25 dBm typical, supporting ACLR measurements to 84 dB with noise correction.

Technical Specifications

• DC coupled: 20 Hz to 3.6 GHz


• AC coupled: 1 MHz to 3.6 GHz Resolution Bandwidth:


• Minimum: 1 Hz; Maximum: 10 MHz


• EMI-standard bandwidths: 200 Hz, 9 kHz, 120 kHz


• Phase noise measurement selection: 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, 1 MHz Noise and Dynamic Range:


• DANL: -158 dBm typical (1 Hz); -155 dBm at 1 GHz; -154 dBm at 7 GHz


• With FSU-B24 preamplifier: -173 dBm (1 Hz)


• TOI: +25 dBm typical


• 1 dB compression: +13 dBm typical


• Total amplitude uncertainty: 0.3 dB to 3.6 GHz


• ACLR: 84 dB with noise correction (3GPP); 77 dB multicarrier Phase Noise Performance:


• -123 dBc/Hz @ 10 kHz offset, 640 MHz carrier


• -160 dBc/Hz @ 10 MHz offset, 640 MHz carrier


• SSB phase noise at 1 kHz: -124 dBc typical Signal Demodulation:


• Standard bandwidth: 28 MHz; Optional: 120 MHz


• I/Q memory: 16 Msamples; Expandable to 705 Msamples (FSQ-B102) Measurement Speed:


• Frequency sweep: 2.5 ms minimum


• Time-domain sweep: 1 µs minimum

Key Features

• Simultaneous spectrum and signal analysis without instrument reconfiguration


• Selectable resolution bandwidths for EMI compliance and phase noise testing


• Linearity error < 0.1 dB down to -70 dB dynamic range


• Extended memory options for complex waveform capture and analysis

Interfaces & Integration

• IEEE 488.2 GPIB


• RS-232-C serial (9-pin D-Sub)


• VGA output (15-pin D-Sub)


• USB connectivity (optional disable via FSQ-B33)