czt Chirp Z Transform czt (x) czt (x, m) czt (x, m, w) czt (x, m, w, a) x: Input scalar or vector m: Total Number of steps w: ratio between points in each step a: point in the complex plane This is an Octave function. 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).