InvFFT

Advanced Analysis Library Only

AnalysisLibErrType InvFFT (double arrayXReal[], double arrayXImg[], int numberOfElements);

Purpose

Note  This function is obsolete. National Instruments recommends that you use CxInvFFTEx instead.

Calculates the inverse Fast Fourier Transform (FFT) of the complex data.

Let X = x + jy be the complex array:

Y = FFT–1(X)

InvFFT performs the operation in place and overwrites the input arrays.

Example

/* Generate two arrays with random numbers and calculate the inverse Fast Fourier Transform. */
double x[256], y[256];
int n;
n = 256;
Uniform (n, 17, x);
Uniform (n, 17, y);
InvFFT (x, y, n);

Parameters

Input
Name Type Description
numberOfElements integer Number of elements in the input arrays.
Output
Name Type Description
arrayXReal double-precision array On input, the real part of the complex array used to compute the inverse FFT.

On output, the real part of inverse FFT.

This operation is performed in place, meaning the values in this array are overwritten.
arrayXImg double-precision array On input, the imaginary part of the complex array used to compute the inverse FFT.

On output, the imaginary part of inverse FFT.

This operation is performed in place, meaning the values in this array are overwritten.

Return Value

Name Type Description
status AnalysisLibErrType A value that specifies the type of error that occurred. Refer to analysis.h for definitions of these constants.