diff options
Diffstat (limited to 'gr-vocoder/lib/vocoder_cvsd_encode_sb.cc')
| -rw-r--r-- | gr-vocoder/lib/vocoder_cvsd_encode_sb.cc | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/gr-vocoder/lib/vocoder_cvsd_encode_sb.cc b/gr-vocoder/lib/vocoder_cvsd_encode_sb.cc new file mode 100644 index 000000000..71cf6df8c --- /dev/null +++ b/gr-vocoder/lib/vocoder_cvsd_encode_sb.cc @@ -0,0 +1,189 @@ +/* -*- c++ -*- */ +/* + * Copyright 2007,2010,2011 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. + */ + +/* + * 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 <vocoder_cvsd_encode_sb.h> +#include <gr_io_signature.h> +#include <limits.h> + +/* + * Create a new instance of vocoder_cvsd_encode_sb and return + * a boost shared_ptr. This is effectively the public constructor. + */ +vocoder_cvsd_encode_sb_sptr +vocoder_make_cvsd_encode_sb (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 gnuradio::get_initial_sptr(new vocoder_cvsd_encode_sb (min_step, max_step, + step_decay, accum_decay, K, J, + pos_accum_max, neg_accum_max)); +} + +vocoder_cvsd_encode_sb::vocoder_cvsd_encode_sb (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_decimator ("vocoder_cvsd_encode_sb", + gr_make_io_signature (1, 1, sizeof (short)), + gr_make_io_signature (1, 1, sizeof (unsigned char)), + 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_stepsize(min_step) + +{ + assert(d_K <= 32); + assert(d_J <= d_K); +} + + +vocoder_cvsd_encode_sb::~vocoder_cvsd_encode_sb () +{ + // nothing else required in this example +} + +unsigned char vocoder_cvsd_encode_sb::cvsd_bitwise_sum (unsigned int input) +{ + unsigned int temp=input; + unsigned char bits=0; + + while(temp) { + temp=temp&(temp-1); + bits++; + } + return bits; +} + +int vocoder_cvsd_encode_sb::cvsd_round (double input) +{ + double temp; + temp=input+0.5; + temp=floor(temp); + + return (int)temp; +} + +unsigned int vocoder_cvsd_encode_sb::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 +vocoder_cvsd_encode_sb::work (int noutput_items, + gr_vector_const_void_star &input_items, + gr_vector_void_star &output_items) +{ + const short *in = (const short *) input_items[0]; + unsigned char *out = (unsigned char *) output_items[0]; + + unsigned short i=0; // 2 bytes, 0 .. 65,535 + unsigned char output_bit=0; // 1 byte, 0 .. 255 + unsigned char output_byte=0; // 1 bytes 0.255 + unsigned char bit_count=0; // 1 byte, 0 .. 255 + unsigned int mask=0; // 4 bytes, 0 .. 4,294,967,295 + + // Loop through each input data point + for(i = 0; i < noutput_items*8; i++) { + if((int)in[i] >= d_accum) { // Note: sign((data(n)-accum)) + output_bit=1; + } + else { + output_bit=0; + } + + // Update Accum (i.e. the reference value) + if (output_bit) { + d_accum=d_accum+d_stepsize; + //printf("Addding %d to the accum; the result is: %d.\n", d_stepsize, d_accum); + } + else { + d_accum=d_accum-d_stepsize; + //printf("Subtracting %d to the accum; the result is: %d.\n", d_stepsize, d_accum); + } + + // 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; + } + + // Update runner with the last output bit + // Update Step Size + if (d_loop_counter >= d_J) { // Run this only if you have >= J bits in your shift register + mask=(cvsd_pow(2, d_J) - 1); + if ((cvsd_bitwise_sum(d_runner & mask) >= d_J) || (cvsd_bitwise_sum((~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); + } + } + + // Runner is a shift-register; shift left, add on newest output bit + d_runner = (d_runner<<1) | ((unsigned int) output_bit); + + // Update the ouput type; shift left, add on newest output bit + // If you have put in 8 bits, output it as a byte + output_byte = (output_byte<<1) | output_bit; + bit_count++; + + if (d_loop_counter <= d_K) { + d_loop_counter++; + } + + // If you have put 8 bits, output and clear. + if (bit_count==8) { + // Read in short from the file + *(out++) = output_byte; + + // Reset the bit_count + bit_count=0; + output_byte=0; + } + } // While + + return noutput_items; +} |