Rohde & Schwarz CMU-K20, Руководство по эксплуатации

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Non Signalling: Modulation Measurements CMU-K20/K21/K22/K23/K24
1115.6088.12 4.42 E-11
Output fields and
table The output fields display the following scalar values:
TSC detected Detected training sequence of the current burst received from the
mobile station
(GSM 0 to 7 or Dummy or "---"), see Analyzer tab,
section Table-Oriented Version on p. 4.73 ff.
Avg. Burst Power Average power of current burst (irrespective of the display mode
selected and of the current measurement curve),
Statistic Count Number of bursts per statistics cycle. The colored bar indicates
the relative measurement progress in the statistics cycle.
Bursts out of Percentage of bursts that violate the tolerance limits.
Tolerance
The following scalar values are calculated for the current burst first. From the
current results the average referenced to a statistics cycle (
Average; see averaging
rules in Chapter 3) and the extreme value over all bursts measured so far
(Max/Min) is calculated:
Phase Error Peak Maximum phase error
Phase Error RMS Effective phase error (RMS-averaged over the burst)
Origin Offset Origin offset in the I/Q constellation diagram; calculated in
analogy to 8PSK modulation (see
Fig. 4-18 on page 4.44
and Equation 4-1 )
I/Q Imbalance Amplitude difference between the I and Q components of
the measured signal see (see
Fig. 4-18 on page 4.44 and
Equation 4-2 )
Frequency Error Frequency error
Remote control
READ[:SCALar]:MODulation:XPERror[:GMSK]?
FETCh[:SCALar]:MODulation:XPERror[:GMSK]?
SAMPle[:SCALar]:MODulation:XPERror[:GMSK]?
CALCulate:MODulation:XPERror[:GMSK]:LIMit:MATChing?
Measurement
curves (arrays)
The continuous measurement curve in the test diagram shows the phase error in
the burst (in degrees) as a function of time (in symbols). The display mode
(Current, Max./Min., Average) for the measurement curve is indicated in the upper
right corner of the diagram.
The scale of both axes is fixed. The measurement curve comprises the whole
useful part of the normal burst (symbol 0 to 146 ¾). The curve is derived from 588
equidistant measurement points with a ¼ symbol spacing. The y-axis ranges from –
20
°
to +20
°
.
Due to the definition of the phase error (see shaded section on page 4.38 ), the
phase error oscillates around the center of the diagram: The 0
°
line is equal to the
regression line of the phase error trajectory calculated using the Mean Square Error
method.
The two colored, horizontal lines in the test diagram mark the selected tolerance
range of the phase error.
Remote control
READ:ARRay:MODulation:XPERror[:GMSK][:BURSt]...?
FETCh:ARRay:MODulation:XPERror[:GMSK][:BURSt]...?
SAMPle:ARRay:MODulation:XPERror[:GMSK][:BURSt]...?
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