R&S FSW Series, Руководство пользователя

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Measurements and Results
R&S
®
FSW
341 User Manual 1173.9411.02 ─ 43
Example:
●
In the initial measurement, determine the peak on one trace using the average
detector by assigning a marker to that trace. For the marker frequency, perform a
refined measurement using the CISPR or RMS average detector.
●
In the initial measurement, determine the peak on another trace using the peak
detector by assigning another marker to that trace. For this marker frequency, per-
form a refined measurement using the quasipeak detector.
7.13.3.7 Final Measurement at the Marker Position
Finding peaks with the help of an initial marker peak search reduces data to be evalu-
ated and thus measurement time. A final measurement with a special EMI detector can
then refine the intial results.
The R&S FSW EMI measurement performs the final measurement automatically as
soon as a detector for the final test is defined for an EMI marker and the marker is acti-
vated. The final measurement starts immediately after the marker has been set. The
advantage of an immediate final measurement is that it eliminates the risk of measure-
ment errors based on frequency drifts of the disturbance signal.
The final measurement at the marker frequency may have a different detector than
during the initial peak search. Thus, the final measurement consumes much less time
because detectors with a long measurement time are needed only at the critical fre-
quency.
The R&S FSW EMI measurement also allows you to use multiple detectors for the final
measurement. The advantage of multiple detection is that you only need one test run
to see if the results comply with the limits specified in a standard. The detectors for the
final EMI tests are defined in the marker configuration as opposed to the
trace detector
which is used for the initial peak search.)
The results of the final measurement are shown in the Result Summary (see Chap-
ter 7.13.2, "EMI Measurement Results" , on page 332).
Defining a Dwell Time for the Final Measurement
EMC tests often require a specific dwell time for an EMI measurement. The dwell time
defines how long the R&S FSW measures the signal at the frequencies of the marker
positions. The dwell time is identical for all EMI final measurements and is thus defined
in the EMI measurement configuration. Select a dwell time according to the character-
istics of the measured signal. See also
Chapter 7.13.3.2, "Detectors and Dwell Time" ,
on page 334.
7.13.3.8 Limit Checks
General limit line functionality is provided by the R&S FSW base unit. The base unit
also provides various predefined limit lines that you can use for various applications.
The R&S
FSW EMI measurement adds further predefined limit lines designed in com-
pliance with several EMC standards.
Electromagnetic Interference (EMI) Measurement