Chirp z-transform. Compute the frequency response starting at a and stepping by w for m steps. a is a point in the complex plane, and w is the ratio between points in each step (i.e., radius increases exponentially, and angle increases linearly).
To evaluate the frequency response for the range f1 to f2 in a signal with sampling frequency Fs, use the following:m = 32; ## number of points desired w = exp(-j*2*pi*(f2-f1)/((m-1)*Fs)); ## freq. step of f2-f1/m a = exp(j*2*pi*f1/Fs); ## starting at frequency f1 y = czt(x, m, w, a);
If you don't specify them, then the parameters default to a fourier transform: m=length(x), w=exp(-j*2*pi/m), a=1
If x is a matrix, the transform will be performed column-by-column.