Rohde & Schwarz FSQ40 20Hz – 40GHz Spectrum Analyzer

The Rohde & Schwarz FSQ40 is a spectrum and signal analyzer operating from 20 Hz to 40 GHz, combining spectrum analysis with advanced signal demodulation capabilities. The instrument delivers exceptional dynamic range, sensitivity, and measurement speed across demanding RF and microwave applications. With demodulation bandwidth up to 120 MHz, phase noise performance of typically -160 dBc/Hz at 10 MHz offset (640 MHz CF), and displayed average noise level of -162 dBm at 1 GHz with 1 Hz RBW, the FSQ40 enables precise characterization of complex signals.

The analyzer features 16 Msample I/Q memory per channel, extendable to 705 Msample, and continuously variable sample rates from 10 kHz to 81.6 MHz. Resolution bandwidth spans 1 Hz to 50 MHz with FFT filters down to 1 Hz, supporting detailed spectral analysis across the full frequency range. Third order intercept (TOI) typically reaches +25 dBm, while 1 dB compression point is +13 dBm, ensuring linear operation across a wide dynamic range.

Total level uncertainty below 3.6 GHz is 0.3 dB with linearity error less than 0.1 dB down to -70 dB.

Technical Specifications

• Frequency Range: 20 Hz to 40 GHz


• Demodulation Bandwidth: 28 MHz standard; 120 MHz optional (FSQ-B72)


• I/Q Memory: 16 Msample per I/Q channel, extendable to 705 Msample


• IF Digitizer: 14-bit, 81.6 MHz (20.4 MHz IF); 326.4 MHz with FSQ-B72


• Sample Rate: 10 kHz to 81.6 MHz continuously variable


• Resolution Bandwidth: 1 Hz to 50 MHz; FFT filters 1 Hz to 30 kHz


• Video Bandwidth: 1 Hz to 30 MHz


• DANL (preamplifier ON): -162 dBm at 1 GHz (1 Hz RBW); -166 dBm at 26 GHz (10 Hz RBW)


• Phase Noise: -133 dBc/Hz at 10 kHz offset (640 MHz CF); -160 dBc/Hz at 10 MHz offset (640 MHz CF)


• Third Order Intercept (TOI): +25 dBm typical


• 1 dB Compression Point: +13 dBm typical


• ACLR (3GPP): 77 dB standard; 84 dB with noise correction


• Total Level Uncertainty (f < 3.6 GHz): 0.3 dB


• Display Linearity: 0.1 dB (0 dB to -70 dB)


• Sweep Time (Frequency Domain): 2.5 ms

Key Features

• Digital demodulation for Bluetooth, GSM/EDGE, 3GPP WCDMA/HSDPA/TD-SCDMA, CDMA2000, WLAN 802.11a/b/g/j, WiMAX 802.16


• Vector signal analysis with general-purpose measurement functions


• Spectrum and code domain power measurements


• Time-selective spectrum analysis with gating


• Fast adjacent channel power (ACP) measurement in time domain


• CCDF statistical signal analysis


• RMS detector with 100 dB dynamic range


• Harmonic distortion and spurious emission measurements (up to 100,001 points across 20 segments)


• Phase noise measurement with R&S FS-K40 Application Firmware

Typical Applications

• Wireless communications development and component testing


• Electromagnetic compatibility (EMC) measurements


• Multi-carrier signal analysis


• Time-domain signal characterization


• Harmonic and spurious content assessment