1 files changed, 115 insertions, 0 deletions
diff --git a/src/fm_demod.c b/src/fm_demod.c
new file mode 100644
index 0000000..bf667d1
--- /dev/null
+++ b/src/fm_demod.c
@@ -0,0 +1,115 @@
+/*---------------------------------------------------------------------------*\
+
+  FILE........: fm_demod.c
+  AUTHOR......: David Rowe
+  DATE CREATED: Feb 24 2015
+
+  Given an input raw file (44.4 kHz, 16 bit shorts) with a FM signal centered
+  11.1 kHz, outputs a file of demodulated audio samples.
+
+\*---------------------------------------------------------------------------*/
+
+/*
+  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_fm.h"
+#include "octave.h"
+
+#define N 160
+
+#define TEST_MOD_COMP
+
+int main(int argc, char *argv[])
+{
+    FILE         *fin, *fout;
+    struct FM    *fm;
+    short         buf[N*2];
+    float         rx[N];
+#if defined(TEST_MODE) && !defined(TEST_MODE_COMP)
+    float         rx_out[N];
+#endif
+    COMP          out_comp[N];
+    int           i;
+
+    if (argc < 2) {
+	printf("usage: %s InputFMRawFile OutputSpeechRawFile\n", argv[0]);
+	printf("e.g    %s fm.raw fm_demodulated.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 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 file: %s: %s.\n",
+         argv[2], strerror(errno));
+	exit(1);
+    }
+
+    fm         = fm_create(N);
+    fm->Fs     = 48000.0;
+    fm->fm_max = 3000.0;
+    fm->fd     = 5000.0;
+    fm->fc     = 0;
+
+    while(fread(buf, sizeof(short), N, fin) == N) {
+	for(i=0; i<N; i++) {
+	    rx[i] = ((float)buf[i])/16384;
+        }
+#ifdef TEST_MOD
+	fm_mod(fm, rx, rx_out);
+#else
+#ifdef  TEST_MOD_COMP
+	fm_mod_comp(fm, rx, out_comp);
+#else
+        fm_demod(fm, rx_out, rx);
+#endif
+#endif
+
+
+#ifdef TEST_MOD_COMP
+	for(i=0; i<N; i++) {
+	    buf[i*2    ] = 16384*out_comp[i].real;
+            buf[1+(i*2)] = 16384*out_comp[i].imag;
+        }
+	fwrite(buf, sizeof(short), N*2, fout);
+#else
+	for(i=0; i<N; i++) {
+	    buf[i] = 16384*rx_out[i];
+        }
+        fwrite(buf, sizeof(short), N, fout);
+#endif
+    }
+
+    fm_destroy(fm);
+    fclose(fin);
+    fclose(fout);
+
+    return 0;
+}