Common Analysis and Display Functions
R&S
®
ESW
200
User Manual 1177.6298.02 ─ 08
The Average Detector
The average detector displays the average level of the samples that have been cap-
tured during the measurement.
For average detection, the video voltage (envelope of IF signal) is averaged over the
measurement time. Averaging is digital, i.e. the digitized values of the video voltage
are summed up and divided by the number of samples at the end of the measurement
time. This corresponds to a filtering with a rectangular window in the time domain and
a filtering with sin x/x characteristic in the frequency domain.
Tips regarding measurement time:
●
Unmodulated signals can be measured with the shortest possible measurement
time.
●
Modulated signals require a measurement time determined by the lowest modula-
tion frequency to be averaged.
●
Pulsed signals require a measurement time that is long enough to capture a suffi-
cient number of pulses. For averaging, a sufficient number of pulses is a number
greater than 10.
The RMS Detector
The RMS detector evaluates the root mean square (RMS) value over the current mea-
surement time and displays the resulting value. The integration time corresponds to the
measurement time.
Tips regarding measurement time:
●
Unmodulated signals can be measured with the shortest possible measurement
time.
●
Modulated signals require a measurement time determined by the lowest modula-
tion frequency to be averaged.
●
Pulsed signals require a measurement time that is long enough to capture a suffi-
cient number of pulses. For averaging, a sufficient number of pulses is a number
greater than 10.
The RMS detector and the video bandwidth
When you are using the RMS detector in the spectrum application, the video band-
width (VBW) in the hardware is bypassed.
Duplicate trace averaging with small VBWs and the RMS detector is therefore not pos-
sible. However, the VBW is still considered for calculating the measurement time. This
results in a longer measurement time for small VBW values. Thus, you can reduce the
VBW to get more stable traces even when you are using the RMS detector. Normally, if
the RMS detector is used the measurement time should be increased to get more sta-
ble traces.
The Sample Detector
The sample detector displays the first level value that has been measured in a particu-
lar statistical bin. All other values that have been measured in such a bin are ignored.
Trace Configuration
