R&S FSQ Signal Analyzer - Rohde & Schwarz

R&S FSQ Getting Started
Measurements on Modulated Signals
Since the video bandwidth of the R&S FSQ is limited to 10 MHz, lowpass filtering
occurs during measurements with a resolution bandwidth of 10 MHz. Additional
band-limiting occurs at a resolution bandwidth of 10 MHz due to the lowpass
filtering at the output of the log amplifier. The latter limits the video signal to a
bandwidth of 8 MHz in order to obtain sufficient suppression of the 20.4 MHz IF.
The level range of the signal amplitudes, e.g. during APD white-noise
measurements, is smaller. For broadband-modulated signals such as W-CDMA
signals, the effect depends on the bandwidth occupied by the signal. At a signal
bandwidth of 4 MHz, the amplitude distribution can be measured correctly with the
effective video bandwidth.
5. Selecting the number of samples
For statistics measurements with the R&S FSQ, the number of samples NSamples
is entered for statistical evaluation instead of the sweep time. Since only
statistically independent samples contribute to statistics, the measurement or
sweep time is calculated automatically. It is indicated on the R&S FSQ display.
The samples are statistically independent if the time difference is at least 1/RBW.
The sweep time SWT is, therefore, expressed as follows:
SWT = NSamples /RBW
2.54 Operating Manual 1313.9681.12 - 01