freqz problems

[Raman Venkataramani]

Hello,

I was wondering if this is a known bug. I am running octave version 2.1.50.
In this example, I am computing the frequency response of an FIR filter "h".

octave:96>
octave:96> h=[1, 0.5]
h =

  1.00000  0.50000

octave:97> H=freqz(h, 1, 512, "whole");
octave:98> H2=freqz(h, 1, 2*pi*[0:511]/512);
octave:99> norm(H-H2)
ans = 27.713
octave:100> norm(abs(H)-abs(H2))
ans =  5.3545e-15
octave:101>

I would have expected that H = H2, but only their magnitudes are equal. It
turns out that H is the correct answer and H2 is the reponse of a shifter
version of h with h(2) being the sample at the origin and h(1) is the
sampele at time -1.

Thanks,
Raman



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