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-rw-r--r--gr-utils/octave/plot_freq_response_phase.m38
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diff --git a/gr-utils/octave/plot_freq_response_phase.m b/gr-utils/octave/plot_freq_response_phase.m
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+#
+# Copyright 2001 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio 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, or (at your option)
+# any later version.
+#
+# GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+function plot_freq_response_db (b,...)
+ if (nargin == 1)
+ ## Response of an FIR filter
+ a = 1;
+ elseif (nargin == 2)
+ ## response of an IIR filter
+ a = va_arg ();
+ endif
+
+ [H,w] = freqz (b,a);
+
+ grid;
+ xlabel ('Normalized Frequency (Fs == 1)');
+ ylabel ('Phase (radians)');
+ abs = abs(H);
+ plot (w/(2*pi), atan2(imag(H), real(H)))
+endfunction