Brief Description of Vector Signal Analysis
R&S
®
FSV-K70
44
Operating Manual 1176.7578.02 ─ 09
Within this stage, the R&S
FSV-K70 checks whether the pattern symbols (bits) really
coincide with the symbol decisions at the pre-detected position. E.g. if one out of 20
symbols does not coincide, the "IQ Pattern Search" stage might detect this IQ pattern,
but the "Pattern Symbol Check" stage will decline it.
Note that this stage is only active if the pattern search is switched on.
Reference Signal Generation
The ideal reference signal is generated based on the detected symbols and the specifi-
cations of the signal model, i.e. the modulation scheme and the transmit filter (Tx filter).
Measurement Filtering
Both the measurement signal and the reference signal are filtered with the specified
measurement filter.
Synchronization
In this stage, the measurement signal and the reference signal are correlated. For
PSK, QAM and MSK modulated signals, an estimation algorithm is used in order to
obtain estimates for the signal amplitude, signal timing, carrier frequency error, phase
error, IQ offset, gain imbalance, quadrature error and the amplitude droop. Alterna-
tively, it is possible to disable the estimation algorithm.
For FSK modulated signals, estimates for the signal amplitude, signal timing, carrier
frequency error, FSK deviation error and the carrier frequency drift are calculated. The
measurement signal is subsequently corrected with these estimates. Compensation for
FSK deviation error and carrier frequency drift can be enabled or disabled.
For more information on synchronization see
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●
Result Display
The selected measurement results are displayed on the screen(s). Configuration of the
screens can be performed via the "Display Configuration" dialog (see
A more detailed description of the most important stages is given in the following sec-
tions.
2.4.1 Burst Search
The burst search is performed only if it is switched on. Otherwise, this stage is skipped.
It is recommended that you switch the burst search on if the signal is bursted. This
ensures that all internal estimators are operated in time ranges where the burst power
ramping is up.
In order to eliminate amplitude variations caused by noise or the modulation itself, the
instantaneous power of the whole capture buffer is computed and then a moving aver-
Demodulation Overview
Содержание FSV-K70
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