Receiver Mode
R&S
®
ESR
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User Manual 1175.7068.02 ─ 12
The higher spectral resolution with smaller bandwidths leads to longer measurement
times at each frequency, because the measurement time has to allow the resolution fil-
ters to settle during a sweep at all signal levels and frequencies to be displayed.
For large measurement bandwidths, signal parts that are very far away (e.g. from a dif-
ferent signal) are considered in the measurement and distort the results. The displayed
noise increases.
For small measurement bandwidths, the measurement time increases.
Bandwidths and detectors
If you use the Quasipeak, CISPR Average or RMS Average detector, the R&S
ESR by
default couples the resolution bandwidth to the receiver frequency.
If you need a different bandwidth, you can decouple the bandwidth from the frequency.
When decoupled, you can select any of the supported CISPR bandwidths.
5.2.2
Detectors
The task of the detector is to determine which of the samples that have been recorded
are displayed for each sweep point. The result obtained from the selected detector for
a sweep point is displayed as the signal level at this frequency point in the trace.
The detectors of the R&S
ESR are implemented as digital devices. All detectors work
in parallel in the background, which means that the measurement speed is independ-
ent of the detector combination used for different traces.
The receiver mode of the R&S
ESR provides several detectors, including detectors
that are especially designed for and required by EMI applications.
You can use several detectors at the same time. The combined use of several detec-
tors (multiple detection) is important for EMI measurements. This is due to specifica-
tions in the standards, for example commercial standards specifiy limits for quasipeak
and average values. In that case, multiple detection requires only one measurement.
The R&S
ESR allows you to use different detectors for the bargraph, scan and final
measurement.
Maximum and Minimum peak detector
The max/min detector yields the maximum/minimum level occurred during the set mea-
surement time. The peak detector is reset at the beginning of each measurement.
Regarding measurement time,
●
unmodulated signals can be measured with the shortest possible measurement
time.
●
for pulses, the selected measurement time must be long enough for at least one
pulse to occur during the measurement time.
The peak detectors are digital detectors. Therefore, discharging is irrelevant even with
long measurement times.
Measurement Basics
