shallow zip-file copy from codec2 e9d726bf20

1 files changed, 162 insertions, 0 deletions

diff --git a/src/fdmdv_mod.c b/src/fdmdv_mod.c
new file mode 100644
index 0000000..b47c543
--- /dev/null
+++ b/src/fdmdv_mod.c
@@ -0,0 +1,162 @@
+/*---------------------------------------------------------------------------*\
+
+  FILE........: fdmdv_mod.c
+  AUTHOR......: David Rowe
+  DATE CREATED: April 28 2012
+
+  Given an input file of bits outputs a raw file (8kHz, 16 bit shorts)
+  of FDMDV modem samples ready to send over a HF radio channel.  The
+  input file is assumed to be arranged as codec frames of 56 bits (7
+  bytes) which we send as two 28 bit modem frames.
+
+\*---------------------------------------------------------------------------*/
+
+
+/*
+  Copyright (C) 2012 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_fdmdv.h"
+
+int main(int argc, char *argv[])
+{
+    FILE         *fin, *fout;
+    struct FDMDV *fdmdv;
+    char          *packed_bits;
+    int           *tx_bits;
+    COMP          tx_fdm[2*FDMDV_NOM_SAMPLES_PER_FRAME];
+    short         tx_fdm_scaled[2*FDMDV_NOM_SAMPLES_PER_FRAME];
+    int           frames;
+    int           i, bit, byte;
+    int           sync_bit;
+    int           bits_per_fdmdv_frame;
+    int           bits_per_codec_frame;
+    int           bytes_per_codec_frame;
+    int           Nc;
+#ifdef CHANNEL_SIM
+    COMP          foff_phase_rect;
+    float         foff;
+#endif
+
+    if (argc < 3) {
+	printf("usage: %s InputBitFile OutputModemRawFile [Nc]\n", argv[0]);
+	printf("e.g    %s hts1a.c2 hts1a_fdmdv.raw\n", argv[0]);
+	exit(1);
+    }
+
+    if (strcmp(argv[1], "-")  == 0) fin = stdin;
+    else if ( (fin = fopen(argv[1],"rb")) == NULL ) {
+	fprintf(stderr, "Error opening input bit 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);
+    }
+
+    if (argc == 4) {
+        Nc = atoi(argv[3]);
+
+        if ((Nc < 2) || (Nc > FDMDV_NC_MAX) ) {
+            fprintf(stderr, "Error number of carriers must be between 2 and %d\n",  FDMDV_NC_MAX);
+            exit(1);
+        }
+   }
+    else
+        Nc = FDMDV_NC;
+
+    fdmdv = fdmdv_create(Nc);
+
+    bits_per_fdmdv_frame = fdmdv_bits_per_frame(fdmdv);
+    bits_per_codec_frame = 2*fdmdv_bits_per_frame(fdmdv);
+    bytes_per_codec_frame = (bits_per_codec_frame+7)/8;
+
+    packed_bits = (char*)malloc(bytes_per_codec_frame);
+    assert(packed_bits != NULL);
+    tx_bits = (int*)malloc(sizeof(int)*bits_per_codec_frame);
+    assert(tx_bits != NULL);
+
+#ifdef CHANNEL_SIM
+    foff = -100;
+    foff_phase_rect.real = 1.0; foff_phase_rect.imag = 0.0;
+#endif
+
+    frames = 0;
+
+    while(fread(packed_bits, sizeof(char), bytes_per_codec_frame, fin) == bytes_per_codec_frame) {
+	frames++;
+
+	/* unpack bits, MSB first */
+
+	bit = 7; byte = 0;
+	for(i=0; i<bits_per_codec_frame; i++) {
+	    tx_bits[i] = (packed_bits[byte] >> bit) & 0x1;
+	    bit--;
+	    if (bit < 0) {
+		bit = 7;
+		byte++;
+	    }
+	}
+
+	/* modulate even and odd frames */
+
+	fdmdv_mod(fdmdv, tx_fdm, tx_bits, &sync_bit);
+	assert(sync_bit == 1);
+
+	fdmdv_mod(fdmdv, &tx_fdm[FDMDV_NOM_SAMPLES_PER_FRAME], &tx_bits[bits_per_fdmdv_frame], &sync_bit);
+	assert(sync_bit == 0);
+
+        #ifdef CHANNEL_SIM
+        /* optional freq shift and channel simulation */
+
+        fdmdv_freq_shift(tx_fdm, tx_fdm, foff, &foff_phase_rect, 2*FDMDV_NOM_SAMPLES_PER_FRAME);
+        fdmdv_simulate_channel(&sig_pwr_av, tx_fdm, 2*FDMDV_NOM_SAMPLES_PER_FRAME, 10.0);
+        #endif
+
+	/* scale and save to disk as shorts */
+
+	for(i=0; i<2*FDMDV_NOM_SAMPLES_PER_FRAME; i++)
+	    tx_fdm_scaled[i] = FDMDV_SCALE * tx_fdm[i].real;
+
+ 	fwrite(tx_fdm_scaled, sizeof(short), 2*FDMDV_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);
+    }
+
+    //fdmdv_dump_osc_mags(fdmdv);
+
+    free(tx_bits);
+    free(packed_bits);
+    fclose(fin);
+    fclose(fout);
+    fdmdv_destroy(fdmdv);
+
+    return 0;
+}