Basics on I/Q Data Acquisition and Processing
R&S
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FSWP
33User Manual 1177.5856.02 ─ 07
The Window Length is adapted to comply with Equation 4-1. Since only window
lengths with integer values can be employed, the Sample Rate is adapted, if neces-
sary, to obtain an integer window length value.
If the record length is larger than the window length, multiple windows are combined;
the FFT length is 4096.
A Flatop window function is used.
Advanced FFT mode
The RBW is determined by the advanced FFT parameters, depending on the selected
FFT Calculation Methods method.
4.5.5 FFT Calculation Methods
FFT calculation can be performed using different methods.
Single
In single mode, one FFT is calculated for the entire record length, that means the win-
dow length is identical to the record length.
If the defined FFT Length is larger than the record length, zeros are appended to the
captured data to reach the FFT length.
Figure 4-6: FFT parameters for single FFT calculation
Averaging
In averaging mode, several overlapping FFTs are calculated for each record; the
results are combined to determine the final FFT result for the record.
The number of FFTs to be combined is determined by the Window Overlap and the
Window Length .
Figure 4-7: FFT parameters for averaged FFT calculation
Basics on FFT
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