minimodem: use fsk.h API
This commit is contained in:
Kamal Mostafa
parent
188b899bb0
commit
54f8efde20
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@ -3,7 +3,7 @@ AM_CFLAGS = -Wall -Werror
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INCLUDES = $(DEPS_CFLAGS)
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bin_PROGRAMS = minimodem tscope fsk
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bin_PROGRAMS = minimodem tscope
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SIMPLEAUDIO_SRC=\
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simpleaudio.c \
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@ -11,10 +11,7 @@ SIMPLEAUDIO_SRC=\
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simpleaudio-sndfile.c
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minimodem_LDADD = $(DEPS_LIBS)
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minimodem_SOURCES = minimodem.c tscope_print.c $(SIMPLEAUDIO_SRC)
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fsk_LDADD = $(DEPS_LIBS)
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fsk_SOURCES = fsk.c tscope_print.c $(SIMPLEAUDIO_SRC)
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minimodem_SOURCES = minimodem.c fsk.c $(SIMPLEAUDIO_SRC)
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tscope_LDADD = $(DEPS_LIBS)
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tscope_SOURCES = tscope.c tscope_print.c
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@ -32,7 +32,7 @@ POST_INSTALL = :
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NORMAL_UNINSTALL = :
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PRE_UNINSTALL = :
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POST_UNINSTALL = :
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bin_PROGRAMS = minimodem$(EXEEXT) tscope$(EXEEXT) fsk$(EXEEXT)
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bin_PROGRAMS = minimodem$(EXEEXT) tscope$(EXEEXT)
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subdir = src
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DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
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ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
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@ -47,13 +47,10 @@ am__installdirs = "$(DESTDIR)$(bindir)"
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PROGRAMS = $(bin_PROGRAMS)
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am__objects_1 = simpleaudio.$(OBJEXT) simpleaudio-pulse.$(OBJEXT) \
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simpleaudio-sndfile.$(OBJEXT)
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am_fsk_OBJECTS = fsk.$(OBJEXT) tscope_print.$(OBJEXT) $(am__objects_1)
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fsk_OBJECTS = $(am_fsk_OBJECTS)
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am__DEPENDENCIES_1 =
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fsk_DEPENDENCIES = $(am__DEPENDENCIES_1)
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am_minimodem_OBJECTS = minimodem.$(OBJEXT) tscope_print.$(OBJEXT) \
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am_minimodem_OBJECTS = minimodem.$(OBJEXT) fsk.$(OBJEXT) \
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$(am__objects_1)
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minimodem_OBJECTS = $(am_minimodem_OBJECTS)
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am__DEPENDENCIES_1 =
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minimodem_DEPENDENCIES = $(am__DEPENDENCIES_1)
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am_tscope_OBJECTS = tscope.$(OBJEXT) tscope_print.$(OBJEXT)
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tscope_OBJECTS = $(am_tscope_OBJECTS)
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@ -66,8 +63,8 @@ COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) \
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$(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
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CCLD = $(CC)
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LINK = $(CCLD) $(AM_CFLAGS) $(CFLAGS) $(AM_LDFLAGS) $(LDFLAGS) -o $@
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SOURCES = $(fsk_SOURCES) $(minimodem_SOURCES) $(tscope_SOURCES)
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DIST_SOURCES = $(fsk_SOURCES) $(minimodem_SOURCES) $(tscope_SOURCES)
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SOURCES = $(minimodem_SOURCES) $(tscope_SOURCES)
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DIST_SOURCES = $(minimodem_SOURCES) $(tscope_SOURCES)
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ETAGS = etags
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CTAGS = ctags
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DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
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@ -167,9 +164,7 @@ SIMPLEAUDIO_SRC = \
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simpleaudio-sndfile.c
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minimodem_LDADD = $(DEPS_LIBS)
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minimodem_SOURCES = minimodem.c tscope_print.c $(SIMPLEAUDIO_SRC)
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fsk_LDADD = $(DEPS_LIBS)
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fsk_SOURCES = fsk.c tscope_print.c $(SIMPLEAUDIO_SRC)
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minimodem_SOURCES = minimodem.c fsk.c $(SIMPLEAUDIO_SRC)
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tscope_LDADD = $(DEPS_LIBS)
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tscope_SOURCES = tscope.c tscope_print.c
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all: all-am
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@ -243,9 +238,6 @@ uninstall-binPROGRAMS:
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clean-binPROGRAMS:
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-test -z "$(bin_PROGRAMS)" || rm -f $(bin_PROGRAMS)
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fsk$(EXEEXT): $(fsk_OBJECTS) $(fsk_DEPENDENCIES)
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@rm -f fsk$(EXEEXT)
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$(LINK) $(fsk_OBJECTS) $(fsk_LDADD) $(LIBS)
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minimodem$(EXEEXT): $(minimodem_OBJECTS) $(minimodem_DEPENDENCIES)
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@rm -f minimodem$(EXEEXT)
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$(LINK) $(minimodem_OBJECTS) $(minimodem_LDADD) $(LIBS)
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305
src/fsk.c
305
src/fsk.c
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@ -1,48 +1,12 @@
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#define USE_FFT
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#include <malloc.h>
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#include <string.h>
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#include <math.h> // fabs, hypotf
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#ifdef USE_FFT
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#include <fftw3.h>
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#endif
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#include <errno.h>
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#include <stdio.h>
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#include <ctype.h>
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//#define FSK_DEBUG
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#ifdef FSK_DEBUG
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# define debug_log(format, args...) fprintf(stderr, format, ## args)
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#else
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# define debug_log(format, args...)
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#endif
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typedef struct fsk_plan fsk_plan;
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struct fsk_plan {
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float sample_rate;
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float f_mark;
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float f_space;
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float filter_bw;
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unsigned int n_data_bits;
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unsigned int n_frame_bits;
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#ifdef USE_FFT
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int fftsize; // fftw wants this to be signed. why?
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unsigned int nbands;
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unsigned int band_width;
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unsigned int b_mark;
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unsigned int b_space;
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fftwf_plan fftplan;
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float *fftin;
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fftwf_complex *fftout;
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#endif
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};
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#include "fsk.h"
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fsk_plan *
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@ -335,9 +299,6 @@ fsk_detect_carrier(fsk_plan *fskp, float *samples, unsigned int nsamples,
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if ( max_mag_band < 0 )
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return -1;
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fprintf(stderr, "### TONE freq=%u mag=%.2f ###\n",
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max_mag_band * fskp->band_width, max_mag);
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return max_mag_band;
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}
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@ -358,267 +319,3 @@ fsk_set_tones_by_bandshift( fsk_plan *fskp, unsigned int b_mark, int b_shift )
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fskp->f_space = b_space * fskp->band_width;
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}
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/****************************************************************************/
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#include <assert.h>
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#include <stdlib.h>
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#include "simpleaudio.h"
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#include "tscope_print.h"
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int
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main( int argc, char*argv[] )
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{
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if ( argc < 2 ) {
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fprintf(stderr, "usage: fsk [filename] baud_rate [ mark_hz space_hz ]\n");
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return 1;
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}
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unsigned char textscope = 0;
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int argi = 1;
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if ( argi < argc && strcmp(argv[argi],"-s") == 0 ) {
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textscope = 1;
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argi++;
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}
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simpleaudio *sa;
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char *p;
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for ( p=argv[argi]; *p; p++ )
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if ( !isdigit(*p) )
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break;
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if ( *p ) {
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sa = simpleaudio_open_source_sndfile(argv[argi]);
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argi++;
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} else {
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sa = simpleaudio_open_source_pulseaudio(argv[0], "bfsk demodulator");
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}
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if ( !sa )
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return 1;
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unsigned int sample_rate = simpleaudio_get_rate(sa);
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// unsigned int nchannels = simpleaudio_get_channels(sa);
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unsigned int decode_rate;
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decode_rate = atoi(argv[argi++]);
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unsigned int band_width;
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band_width = decode_rate;
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/*
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* Bell 103: baud=300 mark=1270 space=1070
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* ITU-T V.21: baud=300 mark=1280 space=1080
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*/
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unsigned int bfsk_mark_f = 1270;
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unsigned int bfsk_space_f = 1070;
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unsigned int autodetect_shift = 200;
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// band_width = 10;
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band_width = 100; /* close enough */
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/*
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* Bell 202: baud=1200 mark=1200 space=2200
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*/
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if ( decode_rate >= 400 ) {
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bfsk_mark_f = 1200;
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bfsk_space_f = 2200;
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band_width = 200;
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}
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if ( argi < argc ) {
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assert(argc-argi == 2);
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bfsk_mark_f = atoi(argv[argi++]);
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bfsk_space_f = atoi(argv[argi++]);
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}
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/*
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* Prepare the input sample chunk rate
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*/
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int nsamples_per_bit = sample_rate / decode_rate;
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/*
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* Prepare the fsk plan
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*/
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fsk_plan *fskp = fsk_plan_new(sample_rate,
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bfsk_mark_f, bfsk_space_f,
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band_width, 8);
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if ( !fskp ) {
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fprintf(stderr, "fsk_plan_new() failed\n");
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return 1;
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}
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/*
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* Run the main loop
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*/
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int ret = 0;
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size_t fill_nsamples = nsamples_per_bit * 12;
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size_t buf_nsamples = fill_nsamples;
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float *samples = malloc(buf_nsamples * sizeof(float));
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size_t read_nsamples = fill_nsamples;
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float *read_bufptr = samples;
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float confidence_total = 0;
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unsigned int nframes_decoded = 0;
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int carrier = 0;
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unsigned int noconfidence = 0;
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unsigned int advance = 0;
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while ( 1 ) {
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if ( advance ) {
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memmove(samples, samples+advance,
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(fill_nsamples-advance)*sizeof(float));
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read_bufptr = samples + (fill_nsamples-advance);
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read_nsamples = advance;
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}
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debug_log( "@read samples+%ld n=%lu\n",
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read_bufptr - samples, read_nsamples);
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assert ( read_nsamples <= buf_nsamples );
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assert ( read_nsamples > 0 );
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if ((ret=simpleaudio_read(sa, read_bufptr, read_nsamples)) <= 0)
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break;
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#define CARRIER_AUTODETECT_THRESHOLD 0.10
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#ifdef CARRIER_AUTODETECT_THRESHOLD
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static int carrier_band = -1;
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// FIXME?: hardcoded 300 baud trigger for carrier autodetect
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if ( decode_rate <= 300 && carrier_band < 0 ) {
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unsigned int i;
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for ( i=0; i+fskp->fftsize<=buf_nsamples; i+=fskp->fftsize ) {
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carrier_band = fsk_detect_carrier(fskp,
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samples+i, fskp->fftsize,
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CARRIER_AUTODETECT_THRESHOLD);
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if ( carrier_band >= 0 )
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break;
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}
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advance = i; /* set advance, in case we end up continuing */
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if ( carrier_band < 0 )
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continue;
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// FIXME: hardcoded negative shift
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int b_shift = - (float)(autodetect_shift + fskp->band_width/2.0)
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/ fskp->band_width;
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/* only accept a carrier as b_mark if it will not result
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* in a b_space band which is "too low". */
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if ( carrier_band + b_shift < 1 ) {
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carrier_band = -1;
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continue;
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}
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fsk_set_tones_by_bandshift(fskp, /*b_mark*/carrier_band, b_shift);
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}
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#endif
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debug_log( "--------------------------\n");
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// FIXME: explain
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unsigned int frame_nsamples = nsamples_per_bit * fskp->n_frame_bits;
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// FIXME: explain
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unsigned int try_max_nsamples = nsamples_per_bit;
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// FIXME: explain
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// THIS BREAKS ONE OF THE 1200 TESTS, WHEN I USE AVOID_TRANSIENTS...
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//unsigned int try_step_nsamples = nsamples_per_bit / 4;
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// BUT THIS FIXES IT AGAIN:
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unsigned int try_step_nsamples = nsamples_per_bit / 8;
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if ( try_step_nsamples == 0 )
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try_step_nsamples = 1;
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float confidence;
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unsigned int bits = 0;
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/* Note: frame_start_sample is actually the sample where the
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* prev_stop bit begins (since the "frame" includes the prev_stop). */
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unsigned int frame_start_sample = 0;
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confidence = fsk_find_frame(fskp, samples, frame_nsamples,
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try_max_nsamples,
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try_step_nsamples,
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&bits,
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&frame_start_sample
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);
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#define FSK_MIN_CONFIDENCE 0.5 /* not critical */
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if ( confidence <= FSK_MIN_CONFIDENCE ) {
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if ( carrier ) {
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// FIXME: explain
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#define FSK_MAX_NOCONFIDENCE_BITS 20
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if ( ++noconfidence > FSK_MAX_NOCONFIDENCE_BITS )
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{
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fprintf(stderr, "### NOCARRIER nbytes=%u confidence=%f ###\n",
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nframes_decoded, confidence_total / nframes_decoded );
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carrier = 0;
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confidence_total = 0;
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nframes_decoded = 0;
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#ifdef CARRIER_AUTODETECT_THRESHOLD
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carrier_band = -1;
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#endif
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}
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}
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/* Advance the sample stream forward by try_max_nsamples so the
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* next time around the loop we continue searching from where
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* we left off this time. */
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advance = try_max_nsamples;
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} else {
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if ( !carrier ) {
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fprintf(stderr, "### CARRIER ###\n");
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carrier = 1;
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}
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confidence_total += confidence;
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nframes_decoded++;
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noconfidence = 0;
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/* Advance the sample stream forward past the decoded frame
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* but not past the stop bit, since we want it to appear as
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* the prev_stop bit of the next frame, so ...
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*
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* advance = 1 prev_stop + 1 start + 8 data bits == 10 bits
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*
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* but actually advance just a bit less than that to allow
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* for clock skew, so ...
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*
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* advance = 9.5 bits */
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advance = frame_start_sample + nsamples_per_bit * (float)(fskp->n_data_bits + 1.5);
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debug_log( "@ frame_start=%u advance=%u\n", frame_start_sample, advance);
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char the_byte = isprint(bits)||isspace(bits) ? bits : '.';
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printf( "%c", the_byte );
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fflush(stdout);
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}
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}
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if ( ret != 0 )
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fprintf(stderr, "simpleaudio_read: error\n");
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if ( carrier ) {
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fprintf(stderr, "### NOCARRIER nbytes=%u confidence=%f ###\n",
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nframes_decoded, confidence_total / nframes_decoded );
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}
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simpleaudio_close(sa);
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fsk_plan_destroy(fskp);
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return ret;
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}
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575
src/minimodem.c
575
src/minimodem.c
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@ -1,70 +1,23 @@
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include <assert.h>
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#include <errno.h>
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#include <math.h>
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#include <fftw3.h>
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#include "simpleaudio.h"
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#include "fsk.h"
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#include "tscope_print.h"
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#ifndef MAX
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#define MAX(a,b) ((a)>(b)?(a):(b))
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#endif
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#ifndef MIN
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#define MIN(a,b) ((a)<(b)?(a):(b))
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#endif
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static inline
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float
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band_mag( fftwf_complex * const cplx, unsigned int band, float scalar )
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int
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main( int argc, char*argv[] )
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{
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float re = cplx[band][0];
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float im = cplx[band][1];
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float mag = hypotf(re, im);
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return mag * scalar;
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}
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static inline
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float
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band_mag_bw( fftwf_complex * const cplx, unsigned int band, unsigned int bw_nbands, float scalar )
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{
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float mag = 0;
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unsigned int i;
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for ( i=0; i<bw_nbands; i++ ) {
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float re, im;
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re = cplx[band+i][0];
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im = cplx[band+i][1];
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mag += hypot(re, im);
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}
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return mag * scalar / bw_nbands;
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}
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int main(int argc, char*argv[]) {
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int ret = 1;
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if ( argc < 2 ) {
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fprintf(stderr, "usage: minimodem [filename] baud_rate [ mark_hz space_hz ]\n");
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fprintf(stderr, "usage: minimodem [filename] baud_rate "
|
||||
"[ mark_hz space_hz ]\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
unsigned char textscope = 0;
|
||||
int argi = 1;
|
||||
if ( argi < argc && strcmp(argv[argi],"-s") == 0 ) {
|
||||
textscope = 1;
|
||||
argi++;
|
||||
}
|
||||
|
||||
simpleaudio *sa;
|
||||
|
||||
|
|
@ -76,13 +29,13 @@ int main(int argc, char*argv[]) {
|
|||
sa = simpleaudio_open_source_sndfile(argv[argi]);
|
||||
argi++;
|
||||
} else {
|
||||
sa = simpleaudio_open_source_pulseaudio(argv[0], "bfsk demodulator");
|
||||
sa = simpleaudio_open_source_pulseaudio(argv[0], "FSK demodulator");
|
||||
}
|
||||
if ( !sa )
|
||||
return 1;
|
||||
|
||||
unsigned int sample_rate = simpleaudio_get_rate(sa);
|
||||
unsigned int nchannels = simpleaudio_get_channels(sa);
|
||||
// unsigned int nchannels = simpleaudio_get_channels(sa);
|
||||
|
||||
|
||||
unsigned int decode_rate;
|
||||
|
|
@ -97,8 +50,12 @@ int main(int argc, char*argv[]) {
|
|||
*/
|
||||
unsigned int bfsk_mark_f = 1270;
|
||||
unsigned int bfsk_space_f = 1070;
|
||||
#define CARRIER_AUTODETECT_THRESHOLD 0.10
|
||||
#ifdef CARRIER_AUTODETECT_THRESHOLD
|
||||
unsigned int autodetect_shift = 200;
|
||||
#endif
|
||||
// band_width = 10;
|
||||
band_width = 50; /* close enough */
|
||||
band_width = 100; /* close enough */
|
||||
|
||||
/*
|
||||
* Bell 202: baud=1200 mark=1200 space=2200
|
||||
|
|
@ -109,383 +66,231 @@ int main(int argc, char*argv[]) {
|
|||
band_width = 200;
|
||||
}
|
||||
|
||||
// unsigned int decode_filter_width = decode_rate / 2;
|
||||
// unsigned int decode_filter_width = decode_rate * 1.5;
|
||||
unsigned int decode_filter_width = decode_rate;
|
||||
|
||||
if ( argi < argc ) {
|
||||
assert(argc-argi == 2);
|
||||
bfsk_mark_f = atoi(argv[argi++]);
|
||||
bfsk_space_f = atoi(argv[argi++]);
|
||||
}
|
||||
|
||||
unsigned int bfsk_bw_nbands = (decode_filter_width + (float)band_width/2) / band_width;
|
||||
unsigned int bfsk_bw_nbands_half = bfsk_bw_nbands / 2;
|
||||
|
||||
unsigned int bfsk_mark_band = (bfsk_mark_f +(float)band_width/2) / band_width;
|
||||
unsigned int bfsk_space_band = (bfsk_space_f +(float)band_width/2) / band_width;
|
||||
|
||||
fprintf(stderr, "### mark_band=%u space_band=%u bw_nbands=%u\n",
|
||||
bfsk_mark_band, bfsk_space_band, bfsk_bw_nbands);
|
||||
|
||||
|
||||
// FIXME -- need to account for bfsk_bw_nbands
|
||||
if ( bfsk_mark_band == 0 || bfsk_space_band == 0 ) {
|
||||
fprintf(stderr, __FILE__": mark or space band is at dsp DC\n");
|
||||
// return 1;
|
||||
}
|
||||
if ( bfsk_mark_band == bfsk_space_band ) {
|
||||
fprintf(stderr, __FILE__": inadequate mark/space separation\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
|
||||
|
||||
/* Create the FFT plan */
|
||||
fftwf_plan fftplan;
|
||||
|
||||
int fftsize = sample_rate / band_width;
|
||||
|
||||
if ( fftsize & 1 )
|
||||
fprintf(stderr, __FILE__": WARNING: fftsize %u is not even\n", fftsize);
|
||||
|
||||
unsigned int nbands = fftsize / 2 + 1;
|
||||
|
||||
float *fftin = fftwf_malloc(fftsize * sizeof(float) * nchannels);
|
||||
|
||||
fftwf_complex *fftout = fftwf_malloc(nbands * sizeof(fftwf_complex) * nchannels);
|
||||
|
||||
/*
|
||||
* works only for 1 channel:
|
||||
fftplan = fftwf_plan_dft_r2c_1d(fftsize, fftin, fftout, FFTW_ESTIMATE);
|
||||
*/
|
||||
/*
|
||||
* works for N channels:
|
||||
*/
|
||||
fftplan = fftwf_plan_many_dft_r2c(
|
||||
/*rank*/1, &fftsize, /*howmany*/nchannels,
|
||||
fftin, NULL, /*istride*/nchannels, /*idist*/1,
|
||||
fftout, NULL, /*ostride*/1, /*odist*/nbands,
|
||||
FFTW_ESTIMATE | FFTW_PRESERVE_INPUT );
|
||||
/* Nb. FFTW_PRESERVE_INPUT is needed for the "shift the input window" trick */
|
||||
|
||||
if ( !fftplan ) {
|
||||
fprintf(stderr, __FILE__": fftwf_plan_dft_r2c_1d() failed\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Prepare the input sample chunk rate
|
||||
*/
|
||||
int nsamples = sample_rate / decode_rate;
|
||||
|
||||
/* BLACK MAGIC! Run the decoder 2% fast ... */
|
||||
int nsamples_adjust = nsamples * 0.02;
|
||||
if ( nsamples_adjust == 0 )
|
||||
nsamples_adjust = 1;
|
||||
nsamples -= nsamples_adjust;
|
||||
|
||||
/* normalize fftw output */
|
||||
float magscalar = 1.0 / ((float)nsamples/2.0);
|
||||
|
||||
/* pulseaudio *adds* when downmixing 2 channels to 1; if we're using
|
||||
* only one channel here, we blindly assume that pulseaudio downmixed
|
||||
* from 2, and rescale magnitudes accordingly. */
|
||||
// but sndfile does not do that.
|
||||
// if ( nchannels == 1 )
|
||||
// magscalar /= 2.0;
|
||||
|
||||
float actual_decode_rate = (float)sample_rate / nsamples;
|
||||
fprintf(stderr, "### nsamples=%u ", nsamples);
|
||||
// fprintf(stderr, "### magscalar=%f ", magscalar);
|
||||
fprintf(stderr, "### baud=%.2f mark=%u space=%u ###\n",
|
||||
actual_decode_rate,
|
||||
bfsk_mark_band * band_width,
|
||||
bfsk_space_band * band_width
|
||||
);
|
||||
int nsamples_per_bit = sample_rate / decode_rate;
|
||||
|
||||
|
||||
/* Prepare the text scope output buffer */
|
||||
// sadly, COLUMNS is not exported by default (?)
|
||||
char *columns_env = getenv("COLUMNS");
|
||||
int columns = columns_env ? atoi(columns_env) : 80;
|
||||
int show_nbands = ( (columns - 2 - 10) / nchannels ) - 1 - 10;
|
||||
if ( show_nbands > nbands )
|
||||
show_nbands = nbands;
|
||||
/*
|
||||
* Prepare the fsk plan
|
||||
*/
|
||||
|
||||
fsk_plan *fskp = fsk_plan_new(sample_rate,
|
||||
bfsk_mark_f, bfsk_space_f,
|
||||
band_width, 8);
|
||||
if ( !fskp ) {
|
||||
fprintf(stderr, "fsk_plan_new() failed\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* Prepare the input sample buffer. For 8-bit frames with prev/start/stop
|
||||
* we need 11 data-bits worth of samples, and we will scan through one bits
|
||||
* worth at a time, hence we need a minimum total input buffer size of 12
|
||||
* data-bits. */
|
||||
size_t samplebuf_size = nsamples_per_bit * 12;
|
||||
float *samplebuf = malloc(samplebuf_size * sizeof(float));
|
||||
float *samples_readptr = samplebuf;
|
||||
size_t read_nsamples = samplebuf_size;
|
||||
size_t samples_nvalid = 0;
|
||||
debug_log("samplebuf_size=%lu\n", samplebuf_size);
|
||||
|
||||
/*
|
||||
* Run the main loop
|
||||
*/
|
||||
|
||||
unsigned int bfsk_bits = 0xFFFFFFFF;
|
||||
unsigned char carrier_detected = 0;
|
||||
int ret = 0;
|
||||
|
||||
unsigned long long carrier_nsamples = 0;
|
||||
unsigned long long carrier_nsymbits = 0;
|
||||
int carrier = 0;
|
||||
float confidence_total = 0;
|
||||
unsigned int nframes_decoded = 0;
|
||||
|
||||
ret = 0;
|
||||
unsigned int noconfidence = 0;
|
||||
unsigned int advance = 0;
|
||||
|
||||
while ( 1 ) {
|
||||
|
||||
bzero(fftin, (fftsize * sizeof(float) * nchannels));
|
||||
debug_log("advance=%u\n", advance);
|
||||
|
||||
/* Shift the samples in samplebuf by 'advance' samples */
|
||||
assert( advance <= samplebuf_size );
|
||||
if ( advance == samplebuf_size ) {
|
||||
samples_nvalid = 0;
|
||||
samples_readptr = samplebuf;
|
||||
read_nsamples = samplebuf_size;
|
||||
advance = 0;
|
||||
}
|
||||
if ( advance ) {
|
||||
if ( advance > samples_nvalid )
|
||||
break;
|
||||
memmove(samplebuf, samplebuf+advance,
|
||||
(samplebuf_size-advance)*sizeof(float));
|
||||
samples_nvalid -= advance;
|
||||
samples_readptr = samplebuf + (samplebuf_size-advance);
|
||||
read_nsamples = advance;
|
||||
}
|
||||
|
||||
size_t nframes = nsamples;
|
||||
/* read samples directly into fftin */
|
||||
if ((ret=simpleaudio_read(sa, fftin, nframes)) <= 0)
|
||||
/* Read more samples into samplebuf (fill it) */
|
||||
assert ( read_nsamples > 0 );
|
||||
assert ( samples_nvalid + read_nsamples <= samplebuf_size );
|
||||
ssize_t r;
|
||||
r = simpleaudio_read(sa, samples_readptr, read_nsamples);
|
||||
debug_log("simpleaudio_read(samplebuf+%ld, n=%lu) returns %ld\n",
|
||||
samples_readptr - samplebuf, samples_nvalid, r);
|
||||
if ( r < 0 ) {
|
||||
fprintf(stderr, "simpleaudio_read: error\n");
|
||||
ret = -1;
|
||||
break;
|
||||
carrier_nsamples += nframes;
|
||||
|
||||
#define TRICK
|
||||
|
||||
#ifdef TRICK
|
||||
reprocess_audio:
|
||||
{
|
||||
}
|
||||
#endif
|
||||
else if ( r > 0 )
|
||||
samples_nvalid += r;
|
||||
|
||||
fftwf_execute(fftplan);
|
||||
if ( samples_nvalid == 0 )
|
||||
break;
|
||||
|
||||
/* examine channel 0 only */
|
||||
float mag_mark = band_mag_bw(fftout,
|
||||
bfsk_mark_band - bfsk_bw_nbands_half,
|
||||
bfsk_bw_nbands, magscalar);
|
||||
float mag_space = band_mag_bw(fftout,
|
||||
bfsk_space_band - bfsk_bw_nbands_half,
|
||||
bfsk_bw_nbands, magscalar);
|
||||
|
||||
|
||||
static unsigned char lastbit;
|
||||
|
||||
#if 0 // TEST -- doesn't help?, sometimes gets it wrong
|
||||
// "clarify" mag_mark and mag_space according to whether lastbit
|
||||
// was a mark or a space ... If lastbit was a mark, then enhance
|
||||
// space and vice-versa
|
||||
float clarify_factor = 2.0;
|
||||
if ( lastbit ) {
|
||||
mag_space *= clarify_factor;
|
||||
} else {
|
||||
mag_mark *= clarify_factor;
|
||||
}
|
||||
#endif
|
||||
|
||||
float msdelta = mag_mark - mag_space;
|
||||
|
||||
|
||||
#define CD_MIN_TONEMAG 0.1
|
||||
#define CD_MIN_MSDELTA_RATIO 0.5
|
||||
|
||||
float cd_ms_delta;
|
||||
if ( decode_rate > 600 ) // HORRIBLE HACK
|
||||
cd_ms_delta = 0.3;
|
||||
else
|
||||
cd_ms_delta = 0.1;
|
||||
|
||||
/* Detect bfsk carrier */
|
||||
int carrier_detect /*boolean*/ =
|
||||
1
|
||||
&& mag_mark + mag_space > CD_MIN_TONEMAG
|
||||
|
||||
&& fabs(msdelta) > cd_ms_delta * (mag_mark+mag_space)
|
||||
|
||||
// && MIN(mag_mark, mag_space) < 0.30
|
||||
// && MAX(mag_mark, mag_space) > 0.80
|
||||
|
||||
// && fabs(msdelta) > CD_MIN_MSDELTA_RATIO * MAX(mag_mark, mag_space)
|
||||
|
||||
// && fabs(msdelta) > 0.5
|
||||
;
|
||||
|
||||
#ifdef TRICK
|
||||
|
||||
// EXCELLENT trick -- fixes 300 baud perfectly
|
||||
// shift the input window to "catch up" if the msdelta is small
|
||||
static unsigned int skipped_frames = 0;
|
||||
if ( ! carrier_detect )
|
||||
{
|
||||
|
||||
if ( nframes == nsamples ) {
|
||||
#if 1
|
||||
/* shift by a fraction of the width of one data bit
|
||||
* any of these could work ... */
|
||||
// nframes = nsamples / 2;
|
||||
// nframes = nsamples / 4;
|
||||
// nframes = nsamples / 8;
|
||||
// nframes = nsamples / 16;
|
||||
nframes = 1;
|
||||
nframes = nframes ? nframes : 1;
|
||||
#endif
|
||||
}
|
||||
|
||||
// clamp the shift to half the bit width
|
||||
if ( skipped_frames + nframes > nsamples/2 )
|
||||
nframes = 0;
|
||||
else
|
||||
skipped_frames += nframes;
|
||||
|
||||
if ( nframes ) {
|
||||
size_t framesize = nchannels * sizeof(float);
|
||||
size_t nbytes = nframes * framesize;
|
||||
size_t reuse_bytes = (nsamples-nframes)*framesize;
|
||||
void *in = fftin;
|
||||
memmove(in, in+nbytes, reuse_bytes);
|
||||
in += reuse_bytes;
|
||||
/* read samples directly into fftin */
|
||||
if ((ret=simpleaudio_read(sa, in, nframes)) <= 0)
|
||||
#ifdef CARRIER_AUTODETECT_THRESHOLD
|
||||
/* Auto-detect carrier frequency */
|
||||
static int carrier_band = -1;
|
||||
// FIXME?: hardcoded 300 baud trigger for carrier autodetect
|
||||
if ( decode_rate <= 300 && carrier_band < 0 ) {
|
||||
unsigned int i;
|
||||
for ( i=0; i+fskp->fftsize<=samples_nvalid; i+=fskp->fftsize ) {
|
||||
carrier_band = fsk_detect_carrier(fskp,
|
||||
samplebuf+i, fskp->fftsize,
|
||||
CARRIER_AUTODETECT_THRESHOLD);
|
||||
if ( carrier_band >= 0 )
|
||||
break;
|
||||
carrier_nsamples += nframes;
|
||||
|
||||
if ( textscope ) {
|
||||
int one_line_mode = 0;
|
||||
int show_maxmag = 1;
|
||||
tscope_print(fftout, show_nbands, magscalar,
|
||||
one_line_mode, show_maxmag);
|
||||
printf("\n");
|
||||
}
|
||||
|
||||
goto reprocess_audio;
|
||||
}
|
||||
}
|
||||
|
||||
if ( carrier_detect && textscope ) {
|
||||
if ( skipped_frames )
|
||||
fprintf(stderr, "<skipped %u (of %u) frames>\n",
|
||||
skipped_frames, nsamples);
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
unsigned char bit;
|
||||
|
||||
|
||||
if ( carrier_detect )
|
||||
{
|
||||
unsigned char physical_bit;
|
||||
carrier_nsymbits++;
|
||||
physical_bit = signbit(msdelta) ? 0 : 1;
|
||||
|
||||
#undef NRZI
|
||||
#ifdef NRZI
|
||||
bit = lastbit != physical_bit;
|
||||
lastbit = physical_bit;
|
||||
#else
|
||||
bit = physical_bit;
|
||||
#endif
|
||||
|
||||
#if 0
|
||||
static unsigned char lastbit_strong = 0;
|
||||
if ( fabs(msdelta) < 0.5 ) { // TEST
|
||||
if ( lastbit_strong )
|
||||
bit = !lastbit;
|
||||
lastbit_strong = 0;
|
||||
} else {
|
||||
lastbit_strong = 1;
|
||||
advance = i + fskp->fftsize;
|
||||
if ( advance > samples_nvalid )
|
||||
advance = samples_nvalid;
|
||||
if ( carrier_band < 0 ) {
|
||||
debug_log("autodetected carrier band not found\n");
|
||||
continue;
|
||||
}
|
||||
#endif
|
||||
|
||||
}
|
||||
else
|
||||
bit = 1;
|
||||
|
||||
skipped_frames = 0;
|
||||
|
||||
#ifndef NRZI
|
||||
lastbit = bit;
|
||||
#endif
|
||||
|
||||
// save 11 bits:
|
||||
// stop--- v v--- start bit
|
||||
// v v--- prev stop bit
|
||||
// 1dddddddd01
|
||||
bfsk_bits = (bfsk_bits>>1) | (bit << 10);
|
||||
|
||||
if ( ! carrier_detect )
|
||||
{
|
||||
if ( carrier_detected ) {
|
||||
float samples_per_bit =
|
||||
(float)carrier_nsamples / carrier_nsymbits;
|
||||
float rx_baud_rate =
|
||||
(float)sample_rate / samples_per_bit;
|
||||
fprintf(stderr, "###NOCARRIER (bits=%llu rx=%.2f baud) ###\n",
|
||||
carrier_nsymbits,
|
||||
rx_baud_rate);
|
||||
carrier_detected = 0;
|
||||
// FIXME: hardcoded negative shift
|
||||
int b_shift = - (float)(autodetect_shift + fskp->band_width/2.0)
|
||||
/ fskp->band_width;
|
||||
/* only accept a carrier as b_mark if it will not result
|
||||
* in a b_space band which is "too low". */
|
||||
if ( carrier_band + b_shift < 1 ) {
|
||||
debug_log("autodetected space band too low\n" );
|
||||
carrier_band = -1;
|
||||
continue;
|
||||
}
|
||||
|
||||
fprintf(stderr, "### TONE freq=%u ###\n",
|
||||
carrier_band * fskp->band_width);
|
||||
|
||||
fsk_set_tones_by_bandshift(fskp, /*b_mark*/carrier_band, b_shift);
|
||||
}
|
||||
#endif
|
||||
|
||||
/*
|
||||
* The main processing algorithm: scan samplesbuf for FSK frames,
|
||||
* looking at an entire frame at once.
|
||||
*/
|
||||
|
||||
debug_log( "--------------------------\n");
|
||||
|
||||
unsigned int frame_nsamples = nsamples_per_bit * fskp->n_frame_bits;
|
||||
|
||||
if ( samples_nvalid < frame_nsamples )
|
||||
break;
|
||||
|
||||
// FIXME: explain
|
||||
unsigned int try_max_nsamples = nsamples_per_bit;
|
||||
unsigned int try_step_nsamples = nsamples_per_bit / 8;
|
||||
if ( try_step_nsamples == 0 )
|
||||
try_step_nsamples = 1;
|
||||
|
||||
float confidence;
|
||||
unsigned int bits = 0;
|
||||
/* Note: frame_start_sample is actually the sample where the
|
||||
* prev_stop bit begins (since the "frame" includes the prev_stop). */
|
||||
unsigned int frame_start_sample = 0;
|
||||
|
||||
confidence = fsk_find_frame(fskp, samplebuf, frame_nsamples,
|
||||
try_max_nsamples,
|
||||
try_step_nsamples,
|
||||
&bits,
|
||||
&frame_start_sample
|
||||
);
|
||||
|
||||
#define FSK_MIN_CONFIDENCE 0.5 /* not critical */
|
||||
#define FSK_MAX_NOCONFIDENCE_BITS 20
|
||||
|
||||
if ( confidence <= FSK_MIN_CONFIDENCE ) {
|
||||
if ( carrier ) {
|
||||
// FIXME: explain
|
||||
if ( ++noconfidence > FSK_MAX_NOCONFIDENCE_BITS )
|
||||
{
|
||||
fprintf(stderr, "### NOCARRIER nbytes=%u confidence=%f ###\n",
|
||||
nframes_decoded, confidence_total / nframes_decoded );
|
||||
carrier = 0;
|
||||
confidence_total = 0;
|
||||
nframes_decoded = 0;
|
||||
#ifdef CARRIER_AUTODETECT_THRESHOLD
|
||||
carrier_band = -1;
|
||||
#endif
|
||||
}
|
||||
}
|
||||
|
||||
/* Advance the sample stream forward by try_max_nsamples so the
|
||||
* next time around the loop we continue searching from where
|
||||
* we left off this time. */
|
||||
advance = try_max_nsamples;
|
||||
continue;
|
||||
}
|
||||
|
||||
if ( ! carrier_detected ) {
|
||||
fprintf(stderr, "###CARRIER###\n");
|
||||
carrier_nsamples = 0;
|
||||
carrier_nsymbits = 0;
|
||||
}
|
||||
carrier_detected = carrier_detect;
|
||||
|
||||
if ( textscope ) {
|
||||
|
||||
// printf("%s %c ",
|
||||
// carrier_detected ? "CD" : " ",
|
||||
// carrier_detected ? ( bit ? '1' : '0' ) : ' ');
|
||||
|
||||
int one_line_mode = 0;
|
||||
int show_maxmag = 1;
|
||||
tscope_print(fftout, show_nbands, magscalar,
|
||||
one_line_mode, show_maxmag);
|
||||
|
||||
printf(" ");
|
||||
int i;
|
||||
for ( i=(11-1); i>=0; i-- )
|
||||
printf("%c", bfsk_bits & (1<<i) ? '1' : '0');
|
||||
printf(" ");
|
||||
fflush(stdout);
|
||||
if ( !carrier ) {
|
||||
fprintf(stderr, "### CARRIER ###\n");
|
||||
carrier = 1;
|
||||
}
|
||||
|
||||
if ( ! carrier_detected ) {
|
||||
if ( textscope ) {
|
||||
printf("\n");
|
||||
fflush(stdout);
|
||||
}
|
||||
continue;
|
||||
confidence_total += confidence;
|
||||
nframes_decoded++;
|
||||
noconfidence = 0;
|
||||
|
||||
}
|
||||
/* Advance the sample stream forward past the decoded frame
|
||||
* but not past the stop bit, since we want it to appear as
|
||||
* the prev_stop bit of the next frame, so ...
|
||||
*
|
||||
* advance = 1 prev_stop + 1 start + 8 data bits == 10 bits
|
||||
*
|
||||
* but actually advance just a bit less than that to allow
|
||||
* for clock skew, so ...
|
||||
*
|
||||
* advance = 9.5 bits */
|
||||
advance = frame_start_sample +
|
||||
nsamples_per_bit * (float)(fskp->n_data_bits + 1.5);
|
||||
|
||||
// stop--- v v--- start bit
|
||||
// v v--- prev stop bit
|
||||
if ( ( bfsk_bits & 0b10000000011 )
|
||||
== 0b10000000001 ) { // valid frame: start=space, stop=mark
|
||||
unsigned char byte = ( bfsk_bits >> 2) & 0xFF;
|
||||
if ( textscope )
|
||||
printf("+");
|
||||
if ( byte == 0xFF ) {
|
||||
debug_log( "@ frame_start=%u advance=%u\n",
|
||||
frame_start_sample, advance);
|
||||
|
||||
if ( textscope )
|
||||
printf("idle");
|
||||
|
||||
} else {
|
||||
|
||||
printf("%c", isspace(byte)||isprint(byte) ? byte : '.');
|
||||
fflush(stdout);
|
||||
|
||||
}
|
||||
bfsk_bits = 1 << 10;
|
||||
}
|
||||
if ( textscope ) {
|
||||
printf("\n");
|
||||
fflush(stdout);
|
||||
}
|
||||
char the_byte = isprint(bits)||isspace(bits) ? bits : '.';
|
||||
printf( "%c", the_byte );
|
||||
fflush(stdout);
|
||||
|
||||
} /* end of the main loop */
|
||||
|
||||
if ( carrier ) {
|
||||
fprintf(stderr, "### NOCARRIER nbytes=%u confidence=%f ###\n",
|
||||
nframes_decoded, confidence_total / nframes_decoded );
|
||||
}
|
||||
|
||||
if ( ret != 0 )
|
||||
fprintf(stderr, "simpleaudio_read: error\n");
|
||||
|
||||
simpleaudio_close(sa);
|
||||
|
||||
fftwf_free(fftin);
|
||||
fftwf_free(fftout);
|
||||
fftwf_destroy_plan(fftplan);
|
||||
fsk_plan_destroy(fskp);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -12,8 +12,8 @@ do
|
|||
rate="${f#*-}"
|
||||
rate="${rate%%-*}"
|
||||
|
||||
echo TEST ./fsk "$i" "$rate"
|
||||
./fsk "$i" "$rate" >$TMPDIR/out 2>$TMPDIR/err
|
||||
echo TEST ./minimodem "$i" "$rate"
|
||||
./minimodem "$i" "$rate" >$TMPDIR/out 2>$TMPDIR/err
|
||||
|
||||
t="${f%%-*}"
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue