TD_IDFFT (Inverse Discrete Fast Fourier Transform) is the inverse function of TD_DFFT. TD_DFFT converts a time-domain signal into a frequency-domain signal. TD_IDFFT takes a frequency domain signal and converts it to a time domain signal.
The TD_IDFFT function takes a series containing Fourier coefficients as an input, and returns the original series that was input into the TD_DFFT function to generate the coefficients. The passed in Fourier coefficients can be in either the rectangular (real, imaginary) or polar (amplitude, phase) formats. This process is used for audio and image processing, digital communications, and scientific data analysis.
The following procedure is an example of how to use TD_IDFFT as one of the processing steps necessary to convolve two series using a manual approach:
The same functionality is achieved by using TD_CONVOLVE.
- Use TD_DFFT on series 1 and series 2 to form ARTs named dfftRes1 and dfftRes2, respectively.
- Use TD_BINARYSERIESOP to do point-wise multiplication using dfftRes1 and dfftRes2, and produce an ART named freqRes.
- Use TD_IDFFT on freqRes to get the convolved result of the two series.