FFT Pre-process

Use the 1D FFT > Advanced Settings > Preprocess menu option (FFTPREP GX) to apply FFT pre-processing procedures to a channel. This allows the pre-processed channel to be visually inspected.

FFT Preprocess dialog options

Channel to filter	Specify the input channel to be processed. Script Parameter: FFTPREP.IN
Output pre-processed channel	Specify the output channel for the pre-processed data. Script Parameter: FFTPREP.OUT

Application Notes

This GX creates a channel solely for display purposes, enabling users to review the pre-processed function. The actual FFT processing steps automatically apply the same pre-processing procedures.

FFT pre-processing includes:

• Removing a first-order trend from the data

• Extending the channel length to a power of 2

• Filling gaps using a predictive filter