Computes the inverse complex fast Fourier transform (FFT). Details
![]() |
FFT {X} is the FFT of the complex valued signal. |
![]() |
X returns the complex valued signal. |
![]() |
error returns any error or warning from the VI. Refer to Signal Processing Error Codes for more information about these conditions. |
You can use the Inverse Complex FFT VI to perform an inverse FFT on an array of one of the complex numeric representations.
If Y represents the output sequence, then
.
You can use the Inverse Complex FFT VI to perform the following operations when FFT X has one of the complex LabVIEW and LabVIEW DSC module data types:
The Inverse Complex FFT VI first analyzes the input data and, based on this analysis, inverse Fourier transforms the data by executing one of the preceding options. All of these routines take advantage of the concurrent processing capabilities of the CPU and FPU.
When the number of samples in the input sequence X is a valid power of 2,
for m = 1, 2, 3, ,23,
where n is the number of samples, the Inverse Complex FFT VI computes the inverse FFT by applying the split-radix algorithm. The longest sequence with an inverse complex FFT that the Inverse Complex FFT VI can compute is
.
When the number of samples in the input sequence X is not a valid power of 2,
for m = 1, 2, 3, ,23,
where n is the number of samples, the Inverse Complex FFT VI computes the inverse DFT by applying an efficient DFT algorithm. The longest sequence with an inverse complex DFT that the Inverse Complex FFT VI can compute is
.
![]() | Note The advantages of the inverse FFT include its speed and memory efficiency because the transform is performed in place. The size of the input sequence, however, must be a power of 2. The inverse DFT can efficiently process any size sequence, but the inverse DFT is slower than the inverse FFT and uses more memory because it must store intermediate results during processing. |