Rohde & Schwarz R&S UPP, Руководство пользователя

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Instrument Functions
R&S
®
UPP
382 User Manual 1411.1055.32 ─ 10
●
The digital generator should use all available audio bits; the (overall) signal
should have a level of 1.0 FS and as little dither as possible.
●
The analog analyzer should be operated in the optimum range, preferably in the
"Auto" mode. If the "Fix" or "Lowest" mode is used, it is important to ensure that the
selected range is not significantly higher than the applied total voltage.
The individual distortion components (harmonics or intermodulation products) and thus
the distortion measured values are calculated using FFT. The FFT value is automati-
cally adapted to the measurement signal. The longer the required FFT, the longer the
necessary integration time and therefore the longer the total measurement time. You
can choose the
minimum FFT value when Post FFT is enabled:
By increasing the minimum FFT value you can increase the ratio of measurement
accuracy to measurement speed loading, since the distortion components are then
measured in a narrower band.
If the selected FFT value is not large enough to capture the measurement signal,
increase the FFT gradually by a factor of 2.
The maximum FFT value depends on the bandwidth or sampling rate:
●
at a 22 kHz bandwidth (analog) the FFT value can be increased to a maximum of
64 k,
●
at sampling rates of less than 50 kHz (digital) or at a 40 kHz bandwidth (analog)
the FFT value can be increased to a maximum of 128 k,
●
at sampling rates of greater than 50 kHz (digital) or at an 80 kHz bandwidth (ana-
log) the FFT value can be increased to a maximum of 256 k,
The maximum integration time in the analog analyzer (fast mode) is therefore around
1.4
s.
5.23.1 General Settings
This chapter contains the settings that occur in a number of distortion measurements
where they have the same meaning.
Equalizer
Used for activating/deactivating a precorrector table for the FFT bins.
Distortion Measurements