Receiver Mode
R&S
®
ESRP
121
User Manual 1175.7445.02 ─ 08
carrier or pulse-like interference which is represented in the form of narrow horizontal
lines on the screen.
The accuracy of the frequency axis corresponds to the reference used (internal or
external). The frequency display range (span) can be selected between 1
kHz and
10
MHz in steps of 1, 2 and 5. With the bandwidths 10
Hz to 100
kHz in steps of 1, 3,
10 the frequency resolution can be matched to the span.
In contrast to normal spectrum analyzer operation, the measured values are deter-
mined using FFT from samples recorded from the A/D-converter. Thus the receiver
stays tuned to the center frequency. It may continue to measure with the selected mea-
surement time and display the signal level with the bargraph. For example, the quasi-
peak level measured with one second measurement time may be displayed in the
upper half of the display while in the lower half the spectrum may be refreshed every
few milliseconds.
The measurement time of the bargraph may be longer than the measurement time of
the IF analysis. If the measurement time of the bargraph is set to a smaller value then
the measurement time of the IF analysis, the bargraph will as often be refreshed as the
display of the IF analysis.
The level display of the IF analysis is unweighted. It is independent of the selected
detector for the bargraph measurement, e.g. average or quasi peak. A maximum of
three traces can be displayed in parallel. The display mode "Clear / Write", "Max Hold",
"Min Hold", "Average", "View" or "Blank" may be selected independent for each trace.
The displayed level values do have the full accuracy of the instrument only at the cen-
ter frequency. At all other frequencies, the level is typically lower due to the frequency
response of the IF filter and the preselector.
The IF display does switch on the 6
dB EMI resolution bandwidth filters for the bar-
graph measurement. 3
dB or channel filters are not possible in the IF analysis mode.
The maximum span for the IF analysis is limited to ten times the selected resolution
bandwidth for the bar graph measurement. This is due to the dynamic range of the bar
graph measurement.
5.1.3
Scans
In scan mode, the R&S
ESRP measures in a predefined frequency range with selecta-
ble step width and measurement time for each frequency.
A scan is either based on the current receiver settings or on the settings defined in the
"Scan Table" (see
Chapter 5.1.3.3, "The Scan Table"
Transducer factors or transducer sets and limit lines can be defined and displayed sep-
arately and are not part of the scan data record.
The scanned frequency range is defined by the start and stop frequency set independ-
ently of the scan table. A scan table can thus be defined for each measurement task.
Measurements and Result Displays
