Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / signal-1.1.3 / freqs_plot.m

diff --git a/octave_packages/signal-1.1.3/freqs_plot.m b/octave_packages/signal-1.1.3/freqs_plot.m
new file mode 100644 (file)
index 0000000..db54a49
--- /dev/null
+++ b/octave_packages/signal-1.1.3/freqs_plot.m
@@ -0,0 +1,50 @@
+## Copyright (C) 2003 Julius O. Smith III <jos@ccrma.stanford.edu>
+##
+## This program 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.
+##
+## This program 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
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} freqs_plot (@var{w}, @var{h})
+## Plot the amplitude and phase of the vector @var{h}.
+##
+## @end deftypefn
+
+function freqs_plot(w,h)
+    n = length(w);
+    mag = 20*log10(abs(h));
+    phase = unwrap(arg(h));
+    maxmag = max(mag);
+
+    subplot(211);
+    plot(w, mag, ";Magnitude (dB);");
+    title('Frequency response plot by freqs');
+    axis("labely");
+    ylabel("dB");
+    xlabel("");
+    grid("on");
+    if (maxmag - min(mag) > 100) % make 100 a parameter?
+      axis([w(1), w(n), maxmag-100, maxmag]);
+    else
+      axis("autoy");
+    endif
+
+    subplot(212);
+    plot(w, phase/(2*pi), ";Phase (radians/2pi);");
+    axis("label");
+    title("");
+    grid("on");
+    axis("autoy");
+    xlabel("Frequency (rad/sec)");
+    ylabel("Cycles");
+    axis([w(1), w(n)]);
+endfunction