HP 8590 E & L Series Spectrum Analyzers and HP 8591C Cable TV ...

FFTSNGLS
FFT Single Sweep
Changes the spectrum analyzer’s sweep mode to single sweep mode (if necessary), and then
performs a fast Fourier transform (FFT) on trace A.
Syntax
Equivalent Softkey: SINGLE FFT .
Prerequisite Commands: LN, Sl?
Related Commands: FFI’CONTS, FFTOFF
Example
OUTPUT 7 18 . “SP OHZ # * ”
OUTPUT 7 18 ; “LN ; ”
Sets the spectrum analyzer to zero span.
Changes the amplitude scale to linear:
OUTPUT 718 ; “FFTSNGLS ; ” Ftyforms the FFi?
Description
You should change the frequency span to 0 Hz and the amplitude scale to linear before
executing FFTSNGLS. How FFTSNGLS performs the FFT depends on the current sweep mode,
the trace status of trace A, and if FFTSNGLS is already active.
� If the spectrum analyzer is in the single-sweep mode or trace A is in the view mode when
FFISNGLS is first executed, the spectrum analyzer does an FFT on trace A without updating
the contents of trace A.
� If the spectrum analyzer is in the continuous-sweep mode when FFTSNGLS is executed, the
spectrum analyzer changes to the single sweep mode, and then does an FFT on trace A.
� If the spectrum analyzer is currently performing the FFTSNGLS command, a take sweep is
performed and then an FFI’ is performed on trace A.
FFTSNGLS does the following when performing an FFT:
� If the current detector is the peak detector, the detector is changed to the sample detector.
� Places trace A in both the clear-write and store-blank modes. (When the spectrum analyzer is
in both the clear-write and store-blank modes, the trace data is still taken from the spectrum
analyzer input during every measurement sweep, but the trace is not shown on the spectrum
analyzer display.)
� Places the results of the FFT in trace B, and then changes trace B to the view mode.
Restrictions
Executing FFTSNGLS exits the following functions: windows display mode (WINON), N dB
point measurement (NDBPNT), gate utility functions (GDRVUTIL), TO1 measurement (TOI),
marker table (MKTBL), peak table (PKTBL), percent AM (PCTAM), peak zoom (PKZOOM),
power menu measurements (ACP, ACPE, CHP, and OBW), and Analog+ display mode
(ANLGPLUS).
You can use the results of the FFTCLIP command to determine if the FFT data is valid.
5.174 Programming Commands