Rohde & Schwarz CMU-K20, Operating Manual

Page: 137 / 646

CMU-K20/K21/K22/K23/K24 Non Signalling: Spectrum Measurements
1115.6088.12 4.59 E-11
Attenuation Setting for the external attenuation of the input level (Normal,
Low Noise, Low Distortion)
Freq. Offset Frequency offset compared to the nominal channel frequency
Chan./Trig. Slot Offs. RF channel and trigger slot offset (see Trig. Slot Offset
hotkey on p. 4.18 )
2
nd
parameter
line
The second parameter line contains the following marker values:
Absolute level (in dBm) and frequency offset from the carrier of
reference marker
Level (in dBm) and frequency offset of delta marker 1 (setting
absolute ). With setting relative, the level difference from the
carrier is indicated (same as the diagram units)
Level and time of delta marker 2, see delta marker 1
Info box
The info box indicates the following settings and scalar results:
Ref. Power Absolute value of the measured carrier output power of the BTS.
According to GSM specifications, the
Ref. Power is measured
with a filter bandwidth of 30 kHz so that it differs from the
average burst power determined in the
Power vs. Time menu.
Statistic Count Number of bursts per statistics cycle
Burst Matching Error message if the displayed burst is out of tolerance.
Remote control
The settings are retrieved using the query corresponding to the setting command
(setting command with appended question mark). The reference power and burst
matching are retrieved with a single command:
READ[:SCALar]:SPECtrum:MODulation[:GMSK]?
FETCh[:SCALar]:SPECtrum:MODulation[:GMSK]?
SAMPle[:SCALar]:SPECtrum:MODulation[:GMSK]?
Response:
<RefPow>,<Match>
Bar graph
The bar graph shows the current carrier output power of the BTS and the measured
spectrum due to modulation at up to 11 non-equidistant frequencies that are
symmetrically distributed around the carrier frequency. The diagram is scaled such
that the x-axis indicating the frequency offset from the carrier ranges from –2 MHz
to +2 MHz; the carrier output power forms the 0 dB reference level. The spectral
tolerance mask defined in the
Limit Lines tab (see p. 4.62 ff) is indicated in addition.
The measurement result at particular frequencies can be retrieved by means of
markers. The measurement at every single frequency point can be switched on and
off in the Meas X tab (see p.
4.67 ).
Limit Check The upper limit lines defined in the Limit Lines tab of the configuration menu (see p.
4.62 ff) yield the red polygonal curve in the diagram. If the limit check fails at a
particular test point the corresponding section of the bar across the bottom of the
diagram turns red.
Remote control
READ:ARRay:SPECtrum:MODulation[:GMSK]?
FETCh:ARRay:SPECtrum:MODulation[:GMSK]?
SAMPle:ARRay:SPECtrum:MODulation[:GMSK]?
深圳德标仪器
135-1095-0799