From 243af5da566a37e914b40081d5a0d04116c35cb4 Mon Sep 17 00:00:00 2001
From: Kamal Mostafa <kamal@whence.com>
Date: Tue, 21 Jun 2011 20:27:51 -0700
Subject: [PATCH] fsk: floating point band_width

---
 src/fsk.c       |  3 +--
 src/fsk.h       |  2 +-
 src/minimodem.c | 15 +++++++++------
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/fsk.c b/src/fsk.c
index 650e12e..4ba315c 100644
--- a/src/fsk.c
+++ b/src/fsk.c
@@ -34,7 +34,6 @@ fsk_plan_new(
     fskp->sample_rate = sample_rate;
     fskp->f_mark = f_mark;
     fskp->f_space = f_space;
-    fskp->filter_bw = filter_bw;
     fskp->n_data_bits = n_data_bits;
 
     /* 1 prev_stop + n_data_bits + 1 start + 1 stop == n_data_bits + 3 */
@@ -43,7 +42,7 @@ fsk_plan_new(
 #ifdef USE_FFT
     fskp->band_width = filter_bw;
 
-    float fft_half_bw = (float)fskp->band_width / 2.0;
+    float fft_half_bw = fskp->band_width / 2.0;
     fskp->fftsize = (sample_rate + fft_half_bw) / fskp->band_width;
     fskp->nbands = fskp->fftsize / 2 + 1;
 
diff --git a/src/fsk.h b/src/fsk.h
index 34d9ae4..770afdf 100644
--- a/src/fsk.h
+++ b/src/fsk.h
@@ -28,7 +28,7 @@ struct fsk_plan {
 #ifdef USE_FFT
 	int		fftsize;
 	unsigned int	nbands;
-	unsigned int	band_width;
+	float		band_width;
 	unsigned int	b_mark;
 	unsigned int	b_space;
 	fftwf_plan	fftplan;
diff --git a/src/minimodem.c b/src/minimodem.c
index f342efb..d34276d 100644
--- a/src/minimodem.c
+++ b/src/minimodem.c
@@ -163,7 +163,7 @@ main( int argc, char*argv[] )
 {
     char *modem_mode = NULL;
     int TX_mode = -1;
-    unsigned int band_width = 0;
+    float band_width = 0;
     unsigned int bfsk_mark_f = 0;
     unsigned int bfsk_space_f = 0;
     unsigned int bfsk_n_data_bits = 0;
@@ -221,8 +221,7 @@ main( int argc, char*argv[] )
 			bfsk_n_data_bits = 5;
 			break;
 	    case 'b':
-			// FIXME make band_width float?
-			band_width = atoi(optarg);
+			band_width = atof(optarg);
 			assert( band_width != 0 );
 			break;
 	    case 'M':
@@ -323,6 +322,10 @@ main( int argc, char*argv[] )
 	}
     }
 
+    /* restrict band_width to <= data rate (FIXME?) */
+    if ( band_width > bfsk_data_rate )
+	band_width = bfsk_data_rate;
+
 
     /*
      * Handle transmit mode
@@ -501,7 +504,7 @@ main( int argc, char*argv[] )
 		continue;
 	    }
 
-	    debug_log("### TONE freq=%u ###\n",
+	    debug_log("### TONE freq=%.1f ###\n",
 		    carrier_band * fskp->band_width);
 
 	    fsk_set_tones_by_bandshift(fskp, /*b_mark*/carrier_band, b_shift);
@@ -571,11 +574,11 @@ main( int argc, char*argv[] )
 
 	if ( !carrier ) {
 	    if ( bfsk_data_rate >= 100 )
-		fprintf(stderr, "### CARRIER %u @ %u Hz ###\n",
+		fprintf(stderr, "### CARRIER %u @ %.1f Hz ###\n",
 			(unsigned int)(bfsk_data_rate + 0.5),
 			fskp->b_mark * fskp->band_width);
 	    else
-		fprintf(stderr, "### CARRIER %.2f @ %u Hz ###\n",
+		fprintf(stderr, "### CARRIER %.2f @ %.1f Hz ###\n",
 			bfsk_data_rate,
 			fskp->b_mark * fskp->band_width);
 	    carrier = 1;