Rohde & Schwarz ZNL Series, Руководство пользователя

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Basics on I/Q Data Acquisition and Processing
R&S
®
ZNL
25 User Manual 1178.5989.02 ─ 06
Advanced FFT mode
The RBW is determined by the advanced FFT parameters , depending on the selected
FFT Calculation Methods method.
4.2.5 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 4-4: 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 4-5: FFT parameters for averaged FFT calculation
4.3 Basics on Input from I/Q Data Files
The I/Q data to be evaluated in a particular R&S ZNL application can not only be cap-
tured by the application itself, it can also be loaded from a file, provided it has the cor-
rect format. The file is then used as the input source for the application.
The I/Q data must be stored in a format with the file extension
.iq.tar
. For a detailed
description see Chapter C, "I/Q Data File Format (iq-tar)" , on page 222.
Basics on Input from I/Q Data Files