fft
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Fast fourier transform.
- Usage 1
fft(x)- x
- signal vector or matrix; if x is a matrix a spectrum of each column is computed
- Result
- A matrix containing a complex spectrum for each column (channel) of the input signal x. The transformation length L is set to
[[./npow2|npow2(nrow(x))]]
// (1) fft( X )
// function:
// if X is a vector: compute the fft spectrum of X
// if X is a matrix: compute the fft spectrum of each row of X
// the fft length L is set to the next power of 2 of nrow(X)
// if L is greater than nrow(X), zero padding is applied
// result:
// vector or matrix Y containing one complex spectrum per row;
// nrow(Y) = L+2, ncol(Y) = ncol(X)
fft
fft(x)fft(x, n)
Calculate the FFT of the vector x. If the parameter n is given and n >= nrow(x), then n is used as the signal length. The next possible value of x^2 is used for the FFT length (if necessary, 0 samples are added to x). The result is a complex FFT spectrum with 2^(m-1)+1 complex values (2^m = FFT length)
