DSP Blockset    
FFT

Compute the FFT of the input.

Library

Transforms

Description

The FFT block computes the fast Fourier transform (FFT) of each channel in the M-by-N input matrix, u.

For both sample-based and frame-based inputs, the block assumes that each input column is a frame containing M consecutive samples from an independent channel. The frame size, M, must be a power of two. To work with other frame sizes, use the Zero Pad block to pad or truncate the frame size to a power-of-two length.

The output is a complex M-by-N matrix whose lth column contains the discrete Fourier transform (DFT) of the corresponding input column at M evenly spaced frequency points in the range [0,Fs), where Fs is the input sample rate, Fs = 1/Ts Hz.

The output is always sample-based, and the output port rate is the same as the input port rate.

For convenience, length-M 1-D vector inputs and sample-based length-M row vector inputs are processed as single channels (i.e., as M-by-1 column vectors), and the output has the same dimension as the input.

Dialog Box

See Also

Complex Cepstrum
DSP Blockset
DCT
DSP Blockset
IFFT
DSP Blockset
Zero Pad
DSP Blockset


 Extract Triangular Matrix Filter Realization Wizard