Mercurial > octave-nkf
view scripts/signal/freqz_plot.m @ 18450:694e8f0b3862 stable
freqz: Make frequency response plot visually compatible with Matlab (bug #41464)
* freqz_plot.m: Eliminate the extraneous "pass band" subplot for visual
compatibility with Matlab. Use y-axis labels instead of legends. Always
autoscale the y-axis. Label the frequency axis in units of normalized
radians or Hz depending on a new optional argument.
* freqz.m: Tell freqz_plot whether the frequency vector is in normalized
radians or Hz.
author | Mike Miller <mtmiller@ieee.org> |
---|---|
date | Thu, 13 Feb 2014 00:00:10 -0500 |
parents | d63878346099 |
children | 9d59bc3dc12d |
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## Copyright (C) 2002-2013 John W. Eaton ## ## This file is part of Octave. ## ## Octave is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 3 of the License, or (at ## your option) any later version. ## ## Octave is distributed in the hope that it will be useful, but ## WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ## General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {} freqz_plot (@var{w}, @var{h}) ## @deftypefnx {Function File} {} freqz_plot (@var{w}, @var{h}, @var{freq_hz}) ## Plot the pass band, stop band and phase response of @var{h}. If the ## optional @var{freq_norm} argument is true, the frequency vector @var{w} ## is in units of normalized radians and the x-axis is labeled as such. ## @end deftypefn ## Author: Paul Kienzle <pkienzle@users.sf.net> function freqz_plot (w, h, freq_norm = false) if (nargin < 2 || nargin > 3) print_usage (); endif n = length (w); ## ## exclude zero-frequency ## h = h (2 : length (h)); ## w = w (2 : length (w)); ## n = n-1; mag = 20 * log10 (abs (h)); phase = unwrap (arg (h)); if (freq_norm) x_label = "Normalized Frequency (\\times\\pi rad/sample)"; else x_label = "Frequency (Hz)"; endif subplot (2, 1, 1); plot (w, mag); grid ("on"); axis ([w(1), w(n)], "autoy"); xlabel (x_label); ylabel ("Magnitude (dB)"); subplot (2, 1, 2); plot (w, phase*360/(2*pi)); grid ("on"); axis ([w(1), w(n)], "autoy"); xlabel (x_label); ylabel ("Phase (degrees)"); endfunction