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/*---------------------------------------------------------------------------*\
FILE........: cohpsk_mod.c
AUTHOR......: David Rowe
DATE CREATED: April 5 2015
Given an input file of bits (note one bit per float, soft decision format),
outputs a raw file (8kHz, 16 bit shorts) of COHPSK modem samples
ready to send over a HF radio channel.
\*---------------------------------------------------------------------------*/
/*
Copyright (C) 2015 David Rowe
All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License version 2.1, as
published by the Free Software Foundation. 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 Lesser General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <errno.h>
#include "codec2_cohpsk.h"
#include "codec2_fdmdv.h"
int opt_exists(char *argv[], int argc, char opt[]) {
int i;
for (i=0; i<argc; i++) {
if (strcmp(argv[i], opt) == 0) {
return i;
}
}
return 0;
}
int main(int argc, char *argv[])
{
FILE *fin, *fout;
struct COHPSK *cohpsk;
char tx_bits_char[2*COHPSK_BITS_PER_FRAME];
int tx_bits[2*COHPSK_BITS_PER_FRAME];
COMP tx_fdm[COHPSK_NOM_SAMPLES_PER_FRAME];
short tx_fdm_scaled[COHPSK_NOM_SAMPLES_PER_FRAME];
int diversity;
int i;
if (argc < 3) {
fprintf(stderr, "\n");
fprintf(stderr, "usage: %s InputOneCharPerBitFile OutputModemRawFile [-nd]\n", argv[0]);
fprintf(stderr, "\n");
fprintf(stderr, " --nd non-diversity mode, input frames of %d bits\n", 2*COHPSK_BITS_PER_FRAME);
fprintf(stderr, "\n");
exit(1);
}
if (strcmp(argv[1], "-") == 0) fin = stdin;
else if ( (fin = fopen(argv[1],"rb")) == NULL ) {
fprintf(stderr, "Error opening input file: %s: %s.\n",
argv[1], strerror(errno));
exit(1);
}
if (strcmp(argv[2], "-") == 0) fout = stdout;
else if ( (fout = fopen(argv[2],"wb")) == NULL ) {
fprintf(stderr, "Error opening output modem sample file: %s: %s.\n",
argv[2], strerror(errno));
exit(1);
}
cohpsk = cohpsk_create();
if (opt_exists(argv, argc, "--nd")) {
diversity = 2;
}
else {
diversity = 1;
}
fprintf(stderr, "diversity: %d\n", diversity);
while(fread(tx_bits_char, sizeof(char), COHPSK_BITS_PER_FRAME*diversity, fin) == COHPSK_BITS_PER_FRAME*diversity) {
for(i=0; i<COHPSK_BITS_PER_FRAME*diversity; i++)
tx_bits[i] = tx_bits_char[i];
cohpsk_mod(cohpsk, tx_fdm, tx_bits, COHPSK_BITS_PER_FRAME*diversity);
cohpsk_clip(tx_fdm, COHPSK_CLIP, COHPSK_NOM_SAMPLES_PER_FRAME);
/* scale and save to disk as shorts */
for(i=0; i<COHPSK_NOM_SAMPLES_PER_FRAME; i++)
tx_fdm_scaled[i] = COHPSK_SCALE * tx_fdm[i].real;
fwrite(tx_fdm_scaled, sizeof(short), COHPSK_NOM_SAMPLES_PER_FRAME, fout);
/* if this is in a pipeline, we probably don't want the usual
buffering to occur */
if (fout == stdout) fflush(stdout);
}
fclose(fin);
fclose(fout);
cohpsk_destroy(cohpsk);
return 0;
}
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