Rohde & Schwarz R&S FSP Series, Operating Manual

Page: 69 / 796

Operating Manual 1164.4556.12 - 06 2.45
R&S FSP Getting Started
Measurements on Modulated Signals
➢
Set the APD softkey to ON .
The R&S FSP sets the frequency span to 0 Hz and measures the amplitude
probability distribution (APD). The number of uncorrelated level
measurements used for the measurement is 100000. The mean power and the
peak power are displayed in dBm. The crest factor (peak power – mean power)
is output as well (see
Fig. 2-1 ).
Fig. 2-1 Amplitude probability distribution of white noise
3. Switch to the CCDF display mode.
➢
Set the CCDF softkey to ON
The APD measurement is switched off and the CCDF display mode is switched
on.
Fig. 2-2 The CCDF of white noise
The CCDF trace indicates the probability that a level will exceed the mean
power. The level above the mean power is plotted along the X axis of the
graph.The origin of the axis corresponds to the mean power level. The
probability that a level will be exceeded is plotted along the Y axis.