
12-1
IM DL850E-01EN
12 FFT
You can display the power spectrum of an input waveform in the FFT window. On models with user-defined
computation (/G2 option), you can display up to two FFT waveforms, and you can analyze the following
spectrums in addition to the power spectrum. However, FFT analysis cannot be performed on waveforms stored
through hard disk recording.
Linear spectrums, power spectrum densities, cross spectrums, transfer functions, and coherence functions
Turning the FFT On and Off (Display)
Set whether to perform FFT analysis. If you set this to ON, the FFT window appears.
• ON: FFT analysis is performed.
• OFF: FFT analysis is not performed.
Analysis Source Waveform (Source)
Set the analysis source waveform to one of the waveforms below.
CH1 to CH16,
1
16chVOLT,
2
16chTEMP/VOLT,
2
CAN,
3
LIN,
3
Math1 to Math6
4
1 You can select the channel of an installed module. However, you cannot select the channel of a logic module.
2 When a 16-CH voltage input module or 16-CH temperature/voltage input module is installed. After you select
16chVOLT or 16chTEMP/VOLT, select a sub channel.
3 On the DL850EV when a CAN bus monitor module or CAN & LIN bus monitor module is installed. After you
select CAN or LIN, select a sub channel. You cannot select waveforms whose data type (Value Type) is set to
Logic.
4 You cannot select Math7 or Math8.
When analysis is performed on a linearly scaled channel, the scaled values are used.
Start Point and Number of FFT Points (Start Point and FFT
Points)
Start Point (Start Point)
Set the computation start point. The default setting is −5 div.
Selectable range: −5 div to +5 div
The start point is similar to the settable range of the cursor display position in cursor measurement.
For details, see “Selectable Range of Cursor Positions.”
Number of FFT Points (FFT Points)
You can set the number of points from the start of computation on the T-Y waveform to one of the options below.
1k, 2k, 5k, 10k, 20k, 50k, or 100k