55
Brief Description
bright. Select the marker [2] and press the soft menu key
PEAK. The second marker should now jump to the same
spot where marker [1] already resides (that is the position
of the fundamental), because the level of this is the high-
est. The values displayed for (Delta-) frequency and level
should be “0”. Press the soft menu key NEXT PEAK in or-
der to cause the active marker to position again on the first
harmonic. The values displayed for (Delta-) frequency and
level should be identical to the original ones.
4.4 Setting of the reference level
The reference level in spectrum analyzers is always the le-
vel of the top graticule line. In order to realize the maxi-
mum dynamic range in spectrum measurement, the le-
vel display range of the spectrum analyzer should be fully
used. This means that the highest level in the actual spec-
trum should be as close to the top graticule line (= refe-
rence level) as possible. The maximum value of the level
display (Y axis) of the measurement display is determined
by the reference level. However, take care that the top gra-
ticule line is not exceeded as this would cause overdrive
of the spectrum analyzer input stage. In order to prevent
overdriving the input, the input attenuators of the spect-
rum analyzer are independently selectable and linked to
the reference level. If the reference level in the amplitude
Fig. 4.8: Setting of the reference level
selection menu (key AMPL
4
) is increased by 20dB (0 to
20 dBm), the input attenuator will be automatically swit-
ched to 30 dBm.This will cause the first harmonic of the si-
gnal (marker 2) to disappear in the noise floor.
4.5 Operation in the receiver mode
For the measurement of levels of a signal frequency the
R&S®HMS-X offers the receiver mode. The spectrum ana-
lyzer operates like a receiver which is tuned to a frequency
and measures the level. The menu of the measurement
functions will open by pressing the key MEAS
11
, If the
soft key CF
RX is activated, the R&S®HMS will switch to
the receiver mode and measures the level of the center
frequency set. The most important settings of the mea-
surement parameters are directly accessible in the main
menu of the receiver mode and can be activated by pres-
sing the appropriate keys. In the receiver mode the same
bandwidths are available as in the analyzer mode. Additi-
onally, the bandwidths 200 Hz, 120 kHz, and 1 MHz (–6 dB)
for emi measurements according to CISPR are provided
(only available in combination with R&S®HMS-EMC resp.
R&S®HV213). These can be chosen by pressing the key
BANDW and using the knob.
The R&S®HMS-X receiver mode offers peak, average,
RMS and quasi-peak detectors. The detector is selected
in the main menu of the receiver mode with the soft key
DETECTOR.
The measuring time is the time during which the spectrum
analyzer collects measurement results and combines them
for a result, depending on the detector selected. With the
knob the measuring time may be varied, or it can be
entered directly via the keyboard.
Fig. 4.9: Receiver mode with a center frequency set
The quasi-peak detector is only available in combination with
R&S®HMS-EMC option resp. R&S®HV213 voucher.
If the quasi-peak detector is selected, the measuring time
should be >100 ms in order to measure varying or pulsed signals
correctly.
Fig. 4.7: PEAK SEARCH function
Summary of Contents for HMS-X
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