R&S FSW Series, Руководство пользователя

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Measurements and Results
R&S
®
FSW
340 User Manual 1173.9411.02 ─ 43
7.13.3.6 Initial Measurement - Peak Search
The purpose of an initial peak search is to find signals with a high interference level
quickly. The peak search is performed with a fast detector like the peak or average
detector. The initial peak search is the basis for a possible refined measurement of
interferences with the detectors specific to EMI measurements.
The results of the initial peak search are shown in the Marker Table (see Chap-
ter 7.13.2, "EMI Measurement Results" , on page 332).
Peak searches can be performed automatically or manually.
Automatic peak search
If enabled, the automatic peak search starts as soon as you select the EMI measure-
ment and one or more markers are active. During automatic peak search, the
R&S
FSW looks for the strongest peaks in the frequency range you are measuring and
positions a marker on those peaks after each sweep. If a limit line is assigned to the
trace, the peak search is based on the level difference between the trace and the limit
line. For each active marker a peak is searched. You can use up to 16 markers simul-
taneously.
The largest peak is always assigned to the active marker with the lowest number; sub-
sequent peaks are assigned to the active markers in ascending order.
The R&S FSW allows you to distribute markers among several traces. If you do so, the
marker with the lowest number assigned to a particular trace is positioned on the larg-
est peak of the corresponding trace.
Manual peak search
If automatic peak search is off, you can set the markers to any frequency you need
more information about manually. You can change the marker position with the rotary
knob or the cursor keys, or position it to a particular frequency with the number keys.
Setting markers is the same as setting markers in other Spectrum measurements. For
more information see
Chapter 9.3, "Marker Usage" , on page 515.
Searching for peaks over several traces
You can search for peaks on six traces simultaneously with a different weighting detec-
tor for each trace.
In this case, the R&S FSW searches for peaks on all traces separately, provided that
you have assigned at least one marker to each trace.
A typical selection for EMI measurement is to use the peak and the average detector.
After initial measurement, search for peaks on the peak trace and the average trace
separately so that the distribution of narrowband and wideband sources of interference
can be taken into account.
Electromagnetic Interference (EMI) Measurement