Rohde & Schwarz CMU-K20, Руководство по эксплуатации

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Non Signalling: Spectrum Measurements CMU-K20/K21/K22/K23/K24
1115.6088.12 4.60 E-11
b) Spectrum due to Switching
In the Spectrum due to Switching measurement, the maximum level measured at a series of fixed
frequency points around the selected RF frequency is displayed. The results and the corresponding
settings are indicated in two parameter lines, the test diagram (bar graph), and an info box:
Parameter lines
Bar graph and
info box
Fig. 4-26 Display of results (spectrum due to switching)
The two parameter lines and the info box are identical with the
due to Modulation menu, see above.
Note that, according to GSM specifications, the Ref. Power is measured with a filter bandwidth of
300 kHz so that it slightly differs from the average burst power determined in the Power menu.
Bar graph
The bar graph shows the carrier output power of the mobile station in the Measured
Timeslot and the measured spectrum due to switching at up to 4 non-equidistant
frequencies that are symmetrically distributed around the carrier frequency. The
switching transients are obtained in peak hold mode but can be updated after each
measurement cycle (see
Cont. Stat. Mode parameter in section Measurement
Control (Spectrum Configuration – Control) on p. 4.61 ff.). The diagram is scaled
such that the x-axis indicating the frequency offset from the carrier ranges from –2
MHz to +2 MHz; the y-axis is in absolute power units (dBm). 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:SWITching[:GMSK]?
FETCh:ARRay:SPECtrum:SWITching[:GMSK]?
SAMPle:ARRay:SPECtrum:SWITching[:GMSK]?
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