The Spectrum Application (RF Measurements)
R&S
®
FPL1000
224
User Manual 1178.3370.02 ─ 09
The instrument has to be configured as follows:
Trigger Offset
t2 – t1 = 25 µs
now the gate ranges are relative to t2
Range1 Start
t3 – t2 = 15 µs
start of range 1 relative to t2
Range1 End
t4 – t2 = 553 µs
end of range 1 relative to t2
Measurement Example – Measuring the APD and CCDF of White Noise Gener-
ated by the R&S
FPL1000
Setting the analysis bandwidth
When the amplitude distribution is measured, the analysis bandwidth must be set so
that the complete spectrum of the signal to be measured falls within the bandwidth.
This is the only way of ensuring that all the amplitudes will pass through the IF filter
without being distorted. If the selected bandwidth is too small for a digitally modulated
signal, the amplitude distribution at the output of the IF filter becomes a Gaussian dis-
tribution according to the central limit theorem and thus corresponds to a white noise
signal. The true amplitude distribution of the signal therefore cannot be determined.
A programming example demonstrating a statistics measurement in a remote environ-
ment is provided in
Chapter 11.6.9.7, "Programming Example: Measuring Statistics"
1. Preset the R&S
FPL1000.
2. Set the reference level to
-60
dBm
.
The R&S
FPL1000's intrinsic noise is displayed at the top of the screen.
3. Select the "APD" measurement function from the "Select Measurement" dialog
box.
The R&S
FPL1000 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.
Measurements and Results
