Measurements and result displays
R&S®ESW-K55
19User Manual 1177.6323.02 ─ 10
A typical application for the "Persistence Spectrum" is the analysis of signals that vary
over time. It is an especially powerful tool to provide an overview of a signal, before it
can be analyzed in detail.
Using a "Persistence Spectrum", fast frequency hops can be distinguished clearly from
amplitude drops, whereas conventional analyzers may mislead the user. As opposed
to the spectrogram display, the "Persistence Spectrum" offers a higher level resolution,
as it does not employ color coding for the power.
Another application for the "Persistence Spectrum" is the separation of superimposed
signals if they can be distinguished in terms of probability distribution of frequency/level
pairs.
Figure 4-4 shows a "Persistence Spectrum" of a noise-like signal resulting from a
motor with brushes. A weak GSM signal is clearly visible in the center of the span. A
standard spectrum analyzer cannot resolve the two different signals, as it does not dis-
play probabilities for each signal point.
Figure 4-4: Wideband noise-like signal covering a GSM signal
Markers in the Persistence Spectrum
Markers can be assigned to any of the three traces in the "Persistence Spectrum" dis-
play. Markers on the persistence traces are 2-dimensional markers defined by a fre-
quency and level value, similar to fixed reference markers (see "Defining a Fixed Ref-
erence" on page 97). The marker result indicates the probability of appearance for the
frequency/level pair.
Dedicated fixed reference markers are not supported in "Persistence Spectrum" dis-
plays. Use a normal marker and a delta marker instead.
For more information about markers, see Chapter 7.8, "Marker settings", on page 92.
For more information on how the histogram and persistence are evaluated see Chap-
ter 5.7, "Understanding persistence", on page 48.
Remote command:
LAY:ADD? '1',RIGH,'XFRequency:PSPectrum', see LAYout:ADD[:WINDow]?
on page 168
Results:
TRAC<n>:DATA? TRACEx, TRAC<n>:DATA? PSP, TRAC<n>:DATA? HMAX, see
TRACe<n>[:DATA] on page 181
TRACe<n>[:DATA]:X? on page 182
MMEMory:STORe<n>:PSPectrum on page 184
Marker Table
Displays a table with the current marker values for the active markers.
Real-Time Spectrum result displays