Initial commit from source tarball

Makefile

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+
+CFLAGS=-Ofast -msse2 -ftree-vectorize -funroll-loops -pthread
+LDLIBS= -lm -lsndfile -lasound -lrtlsdr -pthread
+
+# BEWARE on non SSE2 processor, undefined USE_SSE2 in acarsdec.h
+
+acarsdec:	main.o acars.o msk.o soundfile.o alsa.o rtl.o
+	$(CC) main.o acars.o msk.o soundfile.o alsa.o rtl.o -o $@ $(LDLIBS)
+
+main.o:	main.c acarsdec.h
+acars.o:	acars.c acarsdec.h syndrom.h
+msk.o:	msk.c acarsdec.h
+viterbi.o:	viterbi.c acarsdec.h
+rtl.o:	rtl.c acarsdec.h
+soundfile.o:	soundfile.c acarsdec.h
+alsa.o:	alsa.c acarsdec.h
+
+clean:
+	@rm *.o acarsdec

README

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+Acarsdec is a multi-channels acars decoder with built-in rtl_sdr front end.
+
+The 2.x version is a complete rewrite, very few code line remains from 1.x
+
+Features :
+
+ - new and improved msk demodulator
+ - up to four channels decoded simultaneously
+ - multithreaded, sse2 optimized 
+ - error detection AND correction (correct all one error and some two errors)
+ - input from sound file (.wav) , alsa sound card or software defined radio (SRD) via a rtl dongle (http://sdr.osmocom.org/trac/wiki/rtl-sdr) 
+
+The 4 channels decoding is particularly useful with the rtl dongle. It allows to directly listen simultaneously to 4 different frequencies , with a very low cost hardware.
+
+
+Usage :
+ acarsdec  [-v] [-o lv] [-g gain] [-A] -a alsapcmdevice  | -f sndfile | -r rtldevicenumber  f1 [f2] [f3] [f4] 
+
+ -v :			verbose
+ -o lv :		output format : 0 one line by msg., 1 full (default) 
+ -A :			don't display uplink messages (ie : only aircraft messages)
+ -g gain :		set rtl preamp gain in tenth of db. By default use AGC (ie -g 90 for +9db)
+ -p ppm :		set rtl ppm frequency correction
+ -f sndfile :		decode from sound file (ie: a .wav file)
+ -a alsapcmdevice :	decode from soundcard input alsapcmdevice (ie: hw:0,0)
+ -r rtldevicenumber f1 [f2] [f3] [f4] :		decode from rtl dongle number rtldevicenumber receiving at VHF frequencies f1 and optionaly f2 to f4 in Mhz (ie : -r 0 131.525 131.725 131.825 )
+
+Examples :
+
+Decoding from multichannel wav file :
+acarsdec -v  -f test.wav 
+
+Decoding from sound card with short output :
+acarsdec -o 0 -a hw:0,0
+
+Decoding donwlink messages from rtl dongle number 0 on 3 frequencies :
+acarsdec -A -r 0 131.525 131.725 131.825
+
+
+Compilation :
+acarsdec must compile directly on any modern Intel Linux distrib.
+It has been tested on x86_64 with fedora 19.
+If you want to compile it on an other processor, undefine USE_SSE2 in acarsdec.h
+
+It depends of 3 external libraries :
+ - libsndfile for sound file input (rpm package libsndfile-devel on fedora)
+ - libasound  for sound card input (rpm package alsa-lib-devel on fedora)
+ - librtlsdr for software radio rtl dongle input (http://sdr.osmocom.org/trac/wiki/rtl-sdr)
+
+If you don't have or don't need one of these libs, edit the #define at the beginning of acarsdec.h, to opt-out corresponding code and edit the LDLIBS setting in Makefile.
+
+Testing :
+acarsdec-2.x.tar include a test.wav file. It's a 4 channels audio file that contains 7 acars messages.
+
+./acarsdec -o 0 -f test.wav
+#2 .PH-BXR KL1681 5V S53A  
+#4 .LN-DYY DY083J Q0 S46A  
+#2 .LN-DYY DY083J Q0 S47A  
+#1 .F-GTAE AF7728 H1 D65C  #DFB00000/V206,05,124,183,02,00,0
+#1 .LN-DYY        _d       
+#3 .G-DBCK BA031T _d S64A  
+#3 .G-DBCK BA031T Q0 S63A  
+
+Notes :
+Include sse2 vectorized math functions by Julien Pommier (see sse_mathfun.h)