R&S FSMR, Руководство по эксплуатации

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R&S FSMR External Generator Control - Configuration
1166.3363.12 4.23-10 E-1
Calibration mechanism
Calibration means a calculation of the difference between the currently measured power and a
reference curve, independent of the selected type of measurement (transmission/reflection). The
hardware settings used for measuring the reference curve are included in the reference dataset.
Even with normalization switched on, the device settings can be changed in a wide area without
stopping the normalization. This reduces the necessity to carry out a new normalization to a minimum.
For this purpose, the reference dataset (trace with 625 measured values) is stored as a table with 625
points (frequency/level). Differences in level settings between the reference curve and the current
device settings are taken into account automatically. If the span is reduced, a linear interpolation of the
intermediate values is applied. If the span increases, the values at the left or right border of the
reference dataset are extrapolated to the current start or stop frequency, i.e. the reference dataset is
extended by constant values.
An enhancement label is used to mark the different levels of measurement accuracy. This enhancement
label is displayed at the right diagram border when normalization is switched on and a deviation from the
reference setting occurs. Three accuracy levels are defined:
Table 4.23-1 Measurement accuracy levels
Accuracy Enhancement
label
Reason/Limitation
High NOR No difference between reference setting and measurement
Medium APX
(approximation)
Change of the following settings:
•
coupling (RBW, VBW, SWT)
•
reference level, RF attenuation
•
start or stop frequency
•
output level of tracking generator
•
frequency offset of tracking generator
•
detector (max. peak, min. peak, sample, etc.)
Change of frequency:
•
max. 501 points within the set sweep limits (corresponds to a doubling of the
span)
- Aborted
normalization
•
more than 500 extrapolated points within the current sweep limits (in case of span
doubling)
At a reference level (REF LEVEL) of -10 dBm and at a tracking generator output level
of the same value the analyzer operates without overrange reserve, i.e. the analyzer
is in danger of being overloaded if a signal is applied whose amplitude is higher than
the reference line. In this case, either the message "OVLD" for overload is displayed
in the status line or the display range is exceeded (clipping of the trace at the upper
diagram border = Overrange).
Overloading can be avoided as follows:
•
Reducing the output level of the tracking generator (SOURCE POWER,
NETWORK menu)
•
Increasing the reference level (REF LEVEL, AMPT menu)