From 36c0ba64703776f4cc2a77adc00740b05e0b055d Mon Sep 17 00:00:00 2001
From: trondeau <trondeau@221aa14e-8319-0410-a670-987f0aec2ac5>
Date: Sat, 7 Apr 2007 01:31:18 +0000
Subject: merged developer branch trondeau/cvsd -r4801:4904 to add CVSD vocoder
and example code
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@4906 221aa14e-8319-0410-a670-987f0aec2ac5
---
gr-cvsd-vocoder/src/lib/cvsd_decode_bs.cc | 196 ++++++++++++++++++++++++++++++
1 file changed, 196 insertions(+)
create mode 100644 gr-cvsd-vocoder/src/lib/cvsd_decode_bs.cc
(limited to 'gr-cvsd-vocoder/src/lib/cvsd_decode_bs.cc')
diff --git a/gr-cvsd-vocoder/src/lib/cvsd_decode_bs.cc b/gr-cvsd-vocoder/src/lib/cvsd_decode_bs.cc
new file mode 100644
index 0000000000..def2d946e3
--- /dev/null
+++ b/gr-cvsd-vocoder/src/lib/cvsd_decode_bs.cc
@@ -0,0 +1,196 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2007 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 2, 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.
+ */
+
+/*
+ * config.h is generated by configure. It contains the results
+ * of probing for features, options etc. It should be the first
+ * file included in your .cc file.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <cvsd_decode_bs.h>
+#include <gr_io_signature.h>
+
+/*
+ * Create a new instance of cvsd_decode_bs and return
+ * a boost shared_ptr. This is effectively the public constructor.
+ */
+cvsd_decode_bs_sptr
+cvsd_make_decode_bs (short min_step, short max_step, double step_decay,
+ double accum_decay, int K, int J,
+ short pos_accum_max, short neg_accum_max)
+{
+ return cvsd_decode_bs_sptr (new cvsd_decode_bs (min_step, max_step,
+ step_decay, accum_decay, K, J,
+ pos_accum_max, neg_accum_max));
+}
+
+cvsd_decode_bs::cvsd_decode_bs (short min_step, short max_step, double step_decay,
+ double accum_decay, int K, int J,
+ short pos_accum_max, short neg_accum_max)
+ : gr_sync_interpolator ("cvsd_decode_bs",
+ gr_make_io_signature (1, 1, sizeof (unsigned char)),
+ gr_make_io_signature (1, 1, sizeof (short)),
+ 8),
+ d_min_step (min_step), d_max_step(max_step), d_step_decay(step_decay),
+ d_accum_decay(accum_decay), d_K(K), d_J(J),
+ d_pos_accum_max(pos_accum_max), d_neg_accum_max(neg_accum_max),
+ d_accum(0),
+ d_loop_counter(1),
+ d_runner(0),
+ d_runner_mask(0),
+ d_stepsize(min_step)
+
+{
+ assert(d_pos_accum_max <= SHRT_MAX);
+ assert(d_neg_accum_max >= -SHRT_MAX);
+ assert(d_K <= 32);
+ assert(d_J <= d_K);
+
+ // nothing else required in this example
+}
+
+
+cvsd_decode_bs::~cvsd_decode_bs ()
+{
+ // nothing else required in this example
+}
+
+unsigned char cvsd_decode_bs::cvsd_bitwise_sum (unsigned int input)
+{
+ unsigned int temp=input;
+ unsigned char bits=0;
+
+ while(temp) {
+ temp=temp&(temp-1);
+ bits++;
+ }
+ return bits;
+}
+
+int cvsd_decode_bs::cvsd_round (double input)
+{
+ double temp;
+ temp=input+0.5;
+ temp=floor(temp);
+
+ return (int)temp;
+}
+
+unsigned int cvsd_decode_bs::cvsd_pow (short radix, short power)
+{
+ double d_radix = (double) radix;
+ int i_power = (int) power;
+ double output;
+
+ output=pow(d_radix,i_power);
+ return ( (unsigned int) cvsd_round(output));
+}
+
+
+int
+cvsd_decode_bs::work (int noutput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items)
+{
+
+
+ const unsigned char *in = (const unsigned char *) input_items[0];
+ short *out = (short *) output_items[0];
+
+ int i=0;
+ short output_short=0; // 2 bytes 0 .. 65,535
+ unsigned char bit_count=0; // 1 byte, 0 .. 255
+ unsigned int mask=0; // 4 bytes, 0 .. 4,294,967,295
+ unsigned char input_byte=0; // 1 bytes
+ unsigned char input_bit=0; // 1 byte, 0 .. 255
+
+ // Loop through each input data point
+ for(i = 0; i < noutput_items/8.0; i++) {
+
+ input_byte = in[i];
+ // Initiliaze bit counter
+ bit_count=0;
+
+ while(bit_count<8) {
+ // Compute the Appropriate Mask
+ mask=cvsd_pow(2,7-bit_count);
+
+ // Pull off the corresponding bit
+ input_bit = input_byte & mask;
+
+ // Update the bit counter
+ bit_count++;
+
+ // Update runner with the next input bit
+ // Runner is a shift-register; shift left, add on newest output bit
+ d_runner = (d_runner<<1) | ((unsigned int) input_bit);
+
+ // Run this only if you have >= J bits in your shift register
+ if (d_loop_counter>=d_J) {
+ // Update Step Size
+ d_runner_mask=(cvsd_pow(2,d_J)-1);
+ if ((cvsd_bitwise_sum(d_runner & d_runner_mask)>=d_J)||(cvsd_bitwise_sum((~d_runner) & d_runner_mask)>=d_J)) {
+ // Runs of 1s and 0s
+ d_stepsize = std::min( (short) (d_stepsize + d_min_step), d_max_step);
+ }
+ else {
+ // No runs of 1s and 0s
+ d_stepsize = std::max( (short) cvsd_round(d_stepsize*d_step_decay), d_min_step);
+ }
+ }
+
+ // Update Accum (i.e. the reference value)
+ if (input_bit) {
+ d_accum=d_accum+d_stepsize;
+ }
+ else {
+ d_accum=d_accum-d_stepsize;
+ }
+
+ // Multiply by Accum_Decay
+ d_accum=(cvsd_round(d_accum*d_accum_decay));
+
+ // Check for overflow
+ if (d_accum >=((int) d_pos_accum_max)) {
+ d_accum=(int)d_pos_accum_max;
+ }
+ else if (d_accum <=((int) d_neg_accum_max)) {
+ d_accum=(int)d_neg_accum_max;
+ }
+
+ // Find the output short to write to the file
+ output_short=((short) d_accum);
+
+ if (d_loop_counter <= d_K) {
+ d_loop_counter++;
+ }
+
+ *(out++) = output_short;
+ } // while ()
+
+ } // for()
+
+ return noutput_items;
+}
--
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