[Octave-bug-tracker] [bug #53855] [octave forge] (signal) butter band pass filter with higher order has round-off errors

[Renato]

Follow-up Comment #5, bug #53855 (project octave):

The MatLab documentation is not very well intuitive :-(

The documentation also says to use "hfvt", but it´s not implemented in
Octave.

How to use ZPK Design instead a TF Design of this code below? :-)

++
n = 5;
hpf = 50;
lpf = 10*hpf;
sampling_rate = 44100;

typenoise = noise(60*sampling_rate, 1, 'pink');
[b,a] = butter(n, [hpf/(sampling_rate/2), lpf/(sampling_rate/2)]);
filtered = filter(b, a, typenoise);

freqz (b, a, 4096, sampling_rate)
ax = findall (gcf, 'type', 'axes');
set (ax, 'xlim', [hpf/4 lpf*4]);
set (ax, 'xscale', 'log');
subplot (2, 1, 1);
set (gca, 'ylim', [-35 3]);
--

Thank you,
Renato

    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?53855>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/