| Frequency range | 20 Hz to 3.6 GHz | 20 Hz to 8 GHz | 20 Hz to 26.5 GHz | 20 Hz to 40 GHz | 
            
                | Reference frequency | aging: 1 x 10 –7/year, with R&S®FSU-B4 option: 2 x 10 –8 | 
            
                | Spectral purity | 
            
                | Phase noise | typ. –133 dBc (1 Hz) at 10 kHz carrier offset, carrier frequency 500 MHz | 
            
                | Distortion | 1 Hz | 
            
                | Sweep time | 
            
                | Span >10 Hz | 2.5 ms to 16 000 s | 
            
                | Span 0 Hz (zero span) | 1 μs to 16 000 s | 
            
                | RBW | 10 Hz to 50 MHz, FFT filter: 1 Hz to 30 kHz, channel filter, EMI bandwidth | 
            
                | VBW | 1 Hz to 30 MHz | 
            
                | Display range | DANL to +30 dBm | 
            
                | DANL (1 Hz RBW) | 
            
                | 1 GHz | typ. –158 dBm | typ. –155 dBm | typ. –156 dBm | typ. –155 dBm | 
            
                | 7 GHz | − | typ. –154 dBm | typ. –155 dBm | typ. –153 dBm | 
            
                | 13 GHz | − | − | typ. –151 dBm | typ. –151 dBm | 
            
                | 26 GHz | − | − | typ. –146 dBm | typ. –147 dBm | 
            
                | 40 GHz | − | − | − | typ. –141 dBm | 
            
                | DANL with preamplifier ON (R&S®FSU-B25), 1 GHz, 1 Hz RBW
 | –162 dBm | –162 dBm | –162 dBm | –162 dBm | 
            
                | Displayed averagenoise level with preamplifier ON (R&S®FSU-B24), 26 GHz, 10 Hz RBW
 | − | − | typ. –166 | typ. –166 dBm | 
            
                | DANL with preamplifier ON (R&S®FSU-B23), 26 GHz, 1 Hz RBW
 | − | − | –150 dBm | − | 
            
                | Trace detectors | Max Peak, Min Peak, Auto Peak, Sample, RMS, Average, Quasi Peak | 
            
                | Total measurement uncertainty, f < 3.6 GHz | 0.3 dB | 
            
                | Display linearity | 0.1 dB (0 dB to –70 dB) |