12-6
IM DL850E-01EN
Notes about FFT Computation
Notes about Displaying Power Spectrums
• You cannot display a power spectrum if the display record length is less than the number of computed data
points.
• The following settings are shared for all computation channel: FFT Points, Window, and Start Point.
• When using the commands in the menu that appears when you press the ZOOM key to zoom FFT waveforms
horizontally, you cannot set the number of displayed waveform points to 50 or less.
Notes about Computation
• Computation is normally performed on the sampled data in the acquisition memory. For waveforms that
are acquired in Envelope mode, computation is performed on the maximum and minimum values at each
acquisition interval.
• FFT computation can be performed through the configuration of settings in the Math menu or the FFT menu.
The data point , window function and unit settings are shared for the Math and FFT menus. When you change
the settings in one menu, the settings in the other menu are also changed.
• • On models that do not have user-defined computation (/G2 option), when you enter the FFT menu and turn
FFT computation on, the Math7 operators become invalid, and Math7 cannot be used. On models that do
have user defined computation, when you enter the FFT menu and set FFT 1 and FFT 2 to ON, Math7 and
Math8 cannot be used.
• When you perform FFT computation on 50 kpoint or more of data using the FFT menu, you cannot use
computed waveforms.
• An icon (
) appears in the center of the top of the screen when FFT computation is being executed.
• FFT analysis cannot be performed on waveforms stored through hard disk recording.
Notes about Using the 16-CH Voltage Input Module (720220),
Notes about Using the 16-CH Temperature/Voltage Input Module (720221)
12 FFT
