diff --git a/README.md b/README.md
index 4c24d41..a7c92ce 100644
--- a/README.md
+++ b/README.md
@@ -1,22 +1,34 @@
# libsdr - A simple software defined radio (SDR) library
-**First of all:** I assembled this library for my one entertainment and to learn something about software defined radio. If you are interested into a full-featured, performant SDR framework, consider using GNU radio (http://gnuradio.org).
+**First of all:** I assembled this library for my one entertainment and to learn something about
+software defined radio. If you are interested into a full-featured, performant SDR framework,
+consider using GNU radio (http://gnuradio.org).
-
+
+
+
-Although being simple, libsdr is sufficient to write a simple SDR receiver application (http://github.com/hmatuschek/sdr-rx, above). This RX application supports several input sources (i.e. sound card, files, RTL2382 dongles etc.) and modes (i.e. AM, FM, SSB, CW, etc.).
+Although being simple, libsdr is sufficient to write a simple SDR receiver application
+(http://github.com/hmatuschek/sdr-rx, above). This RX application supports several input sources
+(i.e. sound card, files, RTL2382 dongles etc.) and modes (i.e. AM, FM, SSB, CW, etc.).
## Build
-The only required run-time dependency of `libsdr` is `libpthread`, which is available on all Unix-like OSs like Linux and MacOS X. It is also available for windows if `mingw` is used (http://www.mingw.org) of compilation. There are also some optional dependencies, which allow for the usage of some additional features of the library.
+The only required run-time dependency of `libsdr` is `libpthread`, which is available on all
+Unix-like OSs like Linux and MacOS X. It is also available for windows if `mingw` is used
+(http://www.mingw.org) of compilation. There are also some optional dependencies, which allow for
+the usage of some additional features of the library.
-* `Qt5` (http://qt-project.org) - Enables the `libsdr-gui` library implementing some graphical user interface elements like a spectrum view.
-* `fftw3` (http://www.fftw.org) - Also required by the GUI library and allows for FFT-convolution filters.
+* `Qt5` (http://qt-project.org) - Enables the `libsdr-gui` library implementing some graphical user
+ interface elements like a spectrum view.
+* `fftw3` (http://www.fftw.org) - Also required by the GUI library and allows for FFT-convolution
+ filters.
* `PortAudio` (http://www.portaudio.com) - Allows for sound-card input and output.
* `librtlsdr` (http://rtlsdr.org) - Allows to interface RTL2382U based USB dongles.
-For the compilation of the library, `cmake` (http://www.cmake.org) is also required (as well as a compiler like gcc or clang of cause).
+For the compilation of the library, `cmake` (http://www.cmake.org) is also required (as well as a
+compiler like gcc or clang of cause).
Compiling the library is the canonical cmake path:
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 09f9589..fabce14 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -1,15 +1,19 @@
IF(SDR_WITH_PORTAUDIO)
- add_executable(sdr_wavplay sdr_wavplay.cc)
- target_link_libraries(sdr_wavplay ${LIBS} libsdr)
+# add_executable(sdr_wavplay sdr_wavplay.cc)
+# target_link_libraries(sdr_wavplay ${LIBS} libsdr)
- add_executable(sdr_fm sdr_fm.cc)
- target_link_libraries(sdr_fm ${LIBS} libsdr)
+# add_executable(sdr_fm sdr_fm.cc)
+# target_link_libraries(sdr_fm ${LIBS} libsdr)
- add_executable(sdr_rec sdr_rec.cc)
- target_link_libraries(sdr_rec ${LIBS} libsdr)
+# add_executable(sdr_rec sdr_rec.cc)
+# target_link_libraries(sdr_rec ${LIBS} libsdr)
add_executable(sdr_afsk1200 sdr_afsk1200.cc)
target_link_libraries(sdr_afsk1200 ${LIBS} libsdr)
+
+ add_executable(sdr_rtty sdr_rtty.cc)
+ target_link_libraries(sdr_rtty ${LIBS} libsdr)
+
ENDIF(SDR_WITH_PORTAUDIO)
diff --git a/examples/sdr_afsk1200.cc b/examples/sdr_afsk1200.cc
index 95ecc31..fdc530a 100644
--- a/examples/sdr_afsk1200.cc
+++ b/examples/sdr_afsk1200.cc
@@ -1,335 +1,13 @@
#include "wavfile.hh"
#include "autocast.hh"
#include "interpolate.hh"
+#include "afsk.hh"
+#include "ax25.hh"
+#include "utils.hh"
+
using namespace sdr;
-static const uint16_t crc_ccitt_table[] = {
- 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
- 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
- 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
- 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
- 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
- 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
- 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
- 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
- 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
- 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
- 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
- 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
- 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
- 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
- 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
- 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
- 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
- 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
- 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
- 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
- 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
- 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
- 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
- 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
- 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
- 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
- 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
- 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
- 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
- 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
- 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
- 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
-};
-
-static inline bool check_crc_ccitt(const uint8_t *buf, int cnt)
-{
- uint32_t crc = 0xffff;
- for (; cnt > 0; cnt--, buf++) {
- crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ (*buf)) & 0xff];
- }
- return (crc & 0xffff) == 0xf0b8;
-}
-
-
-class AFSK: public Sink, public Source {
-public:
- AFSK(double baud=1200.0, double Fmark=1200.0, double Fspace=2200.0)
- : Sink(), Source(), _baud(baud), _Fmark(Fmark), _Fspace(Fspace)
- {
- // pass...
- }
-
- virtual ~AFSK() {
- // pass...
- }
-
- virtual void config(const Config &src_cfg) {
- // Check if config is complete
- if (!src_cfg.hasType() || !src_cfg.hasSampleRate()) { return; }
-
- // Check if buffer type matches
- if (Config::typeId() != src_cfg.type()) {
- ConfigError err;
- err << "Can not configure AFSK1200: Invalid type " << src_cfg.type()
- << ", expected " << Config::typeId();
- throw err;
- }
-
- // The input sample rate
- _sampleRate = src_cfg.sampleRate();
-
- // Samples per bit
- _corrLen = int(_sampleRate/_baud);
- // Compute symbol rate:
- _symbolRate = std::min(10*_baud, _baud*_corrLen);
-
- // Samples per symbol (fractional):
- _mu = 0.0; _muIncr = _sampleRate/_symbolRate;
- // Delayline for interpolating sub-sampler
- _dl = Buffer(2*8);
- for (size_t i=0; i<(2*8); i++) { _dl[i] = 0; }
- _dl_idx = 0;
-
- // Assemble phase LUT:
- _markLUT = Buffer< std::complex >(_corrLen);
- _spaceLUT = Buffer< std::complex >(_corrLen);
-
- // Allocate ring-buffers for mark and space symbols
- _markHist = Buffer< std::complex >(_corrLen);
- _spaceHist = Buffer< std::complex >(_corrLen);
-
- // Initialize LUTs and ring-buffers
- double phiMark=0, phiSpace=0;
- for (size_t i=0; i<_corrLen; i++) {
- _markLUT[i] = std::exp(std::complex(0.0, phiMark));
- _spaceLUT[i] = std::exp(std::complex(0.0, phiSpace));
- phiMark += (2.*M_PI*_Fmark)/_sampleRate;
- phiSpace += (2.*M_PI*_Fspace)/_sampleRate;
- _markHist[i] = 0; _spaceHist[i] = 0;
- }
- _lutIdx = 0;
-
- // Get phase increment per symbol
- _phase = 0; _omega = _baud/_symbolRate;
- _omegaMin = _omega - 0.01*_omega;
- _omegaMax = _omega + 0.01*_omega;
- _gainOmega = 0.01;
-
- // Allocate output buffer:
- _buffer = Buffer(src_cfg.bufferSize()/_corrLen + 1);
-
- LogMessage msg(LOG_DEBUG);
- msg << "Config AFSK1200 node: " << std::endl
- << " input sample rate: " << _sampleRate << "Hz" << std::endl
- << " samples per symbol: " << _muIncr << std::endl
- << " symbols per bit: " << _corrLen << std::endl
- << " symbol rate: " << _symbolRate << "Hz" << std::endl
- << " Phase incr/symbol: " << float(_omega);
-
- Logger::get().log(msg);
-
- this->setConfig(Config(Traits::scalarId, _baud, _buffer.size(), 1));
- }
-
-
- virtual void process(const Buffer &buffer, bool allow_overwrite) {
- size_t i=0, o=0;
- while (i1) && (i0);
- // Advance phase
- _phase += _omega;
-
- // Sample bit
- if (_phase >= 1) {
- // Modulo "2 pi"
- _phase = fmodf(_phase, 1.0);
- // Store bit
- _lastBits <<= 1; _lastBits |= (_symbols & 1);
- // Put decoded bit in output buffer
- // transition -> 0; no transition -> 1
- _buffer[o++] = ((_lastBits ^ (_lastBits >> 1) ^ 1) & 1);
- }
-
- // If transition
- if ((_symbols ^ (_symbols >> 1)) & 1) {
- // Phase correction
- /*std::cerr << "Transition at phi=" << _phase << std::endl
- << " update omega from " << _omega << " to "; */
- if (_phase < 0.5) { _omega -= _gainOmega*(_phase); }
- else { _omega += _gainOmega*(1-_phase); }
- // Limit omega
- _omega = std::min(_omegaMax, std::max(_omegaMin, _omega));
- //std::cerr << _omega << std::endl;
- }
- }
- }
- this->send(_buffer.head(o));
- }
-
-
-protected:
- inline double _getSymbol() {
- std::complex markSum(0), spaceSum(0);
- for (size_t i=0; i<_corrLen; i++) {
- markSum += _markHist[i];
- spaceSum += _spaceHist[i];
- }
- double f = markSum.real()*markSum.real() +
- markSum.imag()*markSum.imag() -
- spaceSum.real()*spaceSum.real() -
- spaceSum.imag()*spaceSum.imag();
- return f;
- }
-
-
-protected:
- float _sampleRate, _symbolRate;
- float _baud;
- float _Fmark, _Fspace;
-
- uint32_t _corrLen;
- uint32_t _lutIdx;
- Buffer< std::complex > _markLUT;
- Buffer< std::complex > _spaceLUT;
-
- float _mu, _muIncr;
- Buffer< float > _dl;
- size_t _dl_idx;
-
- Buffer< std::complex > _markHist;
- Buffer< std::complex > _spaceHist;
-
- uint32_t _symbols;
- uint32_t _lastBits;
- float _phase;
- float _omega, _omegaMin, _omegaMax;
- float _gainOmega;
-
- static const uint32_t _phasePeriod = 0x10000u;
- static const uint32_t _phaseMask = 0x0ffffu;
-
- /** Output buffer. */
- Buffer _buffer;
-};
-
-
-class AX25: public Sink, public Source
-{
-public:
- AX25()
- : Sink(), Source()
- {
- // pass...
- }
-
- virtual ~AX25() {
- // pass...
- }
-
- virtual void config(const Config &src_cfg) {
- if (! src_cfg.hasType()) { return; }
- // Check if buffer type matches
- if (Config::typeId() != src_cfg.type()) {
- ConfigError err;
- err << "Can not configure AX25: Invalid type " << src_cfg.type()
- << ", expected " << Config::typeId();
- throw err;
- }
-
- _bitstream = 0;
- _bitbuffer = 0;
- _state = 0;
- _ptr = _rxbuffer;
-
- // Allocate output buffer
- _buffer = Buffer(512);
-
- // propergate config
- this->setConfig(Config(Traits::scalarId, 0, 512, 1));
- }
-
- virtual void process(const Buffer &buffer, bool allow_overwrite) {
- for (size_t i=0; i 2)) {
- *_ptr = 0;
- if (! check_crc_ccitt(_rxbuffer, _ptr-_rxbuffer)) {
- std::cerr << "Got invalid buffer: " << _rxbuffer << std::endl;
- } else {
- std::cerr << "GOT: " << _rxbuffer << std::endl;
- memcpy(_buffer.ptr(), _rxbuffer, _ptr-_rxbuffer);
- this->send(_buffer.head(_ptr-_rxbuffer));
- }
-
- }
- _state = 1;
- _ptr = _rxbuffer;
- _bitbuffer = 0x80;
- continue;
- }
-
- // If 7 ones are received in a row -> error, wait or sync byte
- if ((_bitstream & 0x7f) == 0x7f) { _state = 0; continue; }
-
- // If state == wait for sync byte -> receive next bit
- if (!_state) { continue; }
-
- /* stuffed bit */
- if ((_bitstream & 0x3f) == 0x3e) { continue; }
-
- // prepend bit to bitbuffer
- _bitbuffer |= ((_bitstream & 1) << 8);
-
- // If 8 bits have been received (stored in b8-b1 of _bitbuffer)
- if (_bitbuffer & 1) {
- // Check for buffer overrun
- if ((_ptr-_rxbuffer) >= 512) {
- Logger::get().log(LogMessage(LOG_ERROR, "AX.25 packet too long."));
- // Wait for next sync byte
- _state = 0;
- continue;
- }
-
- // Store received byte and ...
- *_ptr++ = (_bitbuffer >> 1);
- // reset bit buffer
- _bitbuffer = 0x80;
- continue;
- }
- // Shift bitbuffer one to the left
- _bitbuffer >>= 1;
- }
- }
-
-protected:
- uint32_t _bitstream;
- uint32_t _bitbuffer;
- uint32_t _state;
-
- uint8_t _rxbuffer[512];
- uint8_t *_ptr;
-
- Buffer _buffer;
-};
int main(int argc, char *argv[]) {
@@ -338,18 +16,23 @@ int main(int argc, char *argv[]) {
sdr::Logger::get().addHandler(
new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
+ Queue &queue = Queue::get();
+
WavSource src(argv[1], 1024);
if (! src.isOpen()) { std::cout << "Can not open file " << argv[1] << std::endl; return -1; }
AutoCast< int16_t > cast;
- AFSK demod;
+ AFSK demod(1200, 1200, 2200, AFSK::TRANSITION);
AX25 decode;
+ TextDump dump;
src.connect(&cast);
cast.connect(&demod);
demod.connect(&decode);
+ decode.connect(&dump);
Queue::get().addIdle(&src, &WavSource::next);
+ src.addEOS(&queue, &Queue::stop);
Queue::get().start();
Queue::get().wait();
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 503f01f..41310aa 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -2,12 +2,13 @@
set(LIBSDR_SOURCES
buffer.cc node.cc queue.cc traits.cc
portaudio.cc utils.cc wavfile.cc
- exception.cc logger.cc psk31.cc options.cc)
+ exception.cc logger.cc psk31.cc options.cc afsk.cc ax25.cc baudot.cc)
set(LIBSDR_HEADERS sdr.hh math.hh
buffer.hh node.hh queue.hh buffernode.hh filternode.hh traits.hh autocast.hh
siggen.hh portaudio.hh utils.hh wavfile.hh demod.hh firfilter.hh
fftplan.hh fftplan_native.hh exception.hh baseband.hh freqshift.hh subsample.hh
- combine.hh logger.hh psk31.hh interpolate.hh operators.hh options.hh)
+ combine.hh logger.hh psk31.hh interpolate.hh operators.hh options.hh afsk.hh ax25.hh
+ baudot.hh)
if(SDR_WITH_PORTAUDIO)
set(LIBSDR_SOURCES ${LIBSDR_SOURCES} portaudio.cc)
diff --git a/src/afsk.cc b/src/afsk.cc
new file mode 100644
index 0000000..dc8e6ab
--- /dev/null
+++ b/src/afsk.cc
@@ -0,0 +1,168 @@
+#include "afsk.hh"
+#include "logger.hh"
+#include "traits.hh"
+#include "interpolate.hh"
+
+using namespace sdr;
+
+
+AFSK::AFSK(double baud, double Fmark, double Fspace, Mode mode)
+ : Sink(), Source(), _baud(baud), _Fmark(Fmark), _Fspace(Fspace), _mode(mode)
+{
+ // pass...
+}
+
+AFSK::~AFSK() {
+ // pass...
+}
+
+void
+AFSK::config(const Config &src_cfg)
+{
+ // Check if config is complete
+ if (!src_cfg.hasType() || !src_cfg.hasSampleRate()) { return; }
+
+ // Check if buffer type matches
+ if (Config::typeId() != src_cfg.type()) {
+ ConfigError err;
+ err << "Can not configure AFSK1200: Invalid type " << src_cfg.type()
+ << ", expected " << Config::typeId();
+ throw err;
+ }
+
+ // The input sample rate
+ _sampleRate = src_cfg.sampleRate();
+
+ // Samples per bit
+ _corrLen = int(_sampleRate/_baud);
+ // Compute symbol rate:
+ _symbolRate = std::max(_baud, _baud*_corrLen);
+
+ // Samples per symbol (fractional):
+ _muIncr = _sampleRate/_symbolRate;
+ _mu = _muIncr;
+ // Delayline for interpolating sub-sampler
+ _dl = Buffer(2*8);
+ for (size_t i=0; i<(2*8); i++) { _dl[i] = 0; }
+ _dl_idx = 0;
+
+ // Assemble phase LUT:
+ _markLUT = Buffer< std::complex >(_corrLen);
+ _spaceLUT = Buffer< std::complex >(_corrLen);
+
+ // Allocate ring-buffers for mark and space symbols
+ _markHist = Buffer< std::complex >(_corrLen);
+ _spaceHist = Buffer< std::complex >(_corrLen);
+ _symbols = Buffer(_corrLen);
+
+ // Initialize LUTs and ring-buffers
+ double phiMark=0, phiSpace=0;
+ for (size_t i=0; i<_corrLen; i++) {
+ _markLUT[i] = std::exp(std::complex(0.0, phiMark));
+ _spaceLUT[i] = std::exp(std::complex(0.0, phiSpace));
+ phiMark += (2.*M_PI*_Fmark)/_sampleRate;
+ phiSpace += (2.*M_PI*_Fspace)/_sampleRate;
+ // Apply Window functions
+ //_markLUT[i] *= (0.42 - 0.5*cos((2*M_PI*i)/_corrLen) + 0.08*cos((4*M_PI*i)/_corrLen));
+ //_spaceLUT[i] *= (0.42 - 0.5*cos((2*M_PI*i)/_corrLen) + 0.08*cos((4*M_PI*i)/_corrLen));
+ _markHist[i] = 0; _spaceHist[i] = 0; _symbols[i] = 0;
+ }
+ // Ring buffer indices
+ _lutIdx = 0; _symbolIdx = 0;
+
+ // Get phase increment per symbol
+ _phase = 0; _omega = _baud/_symbolRate;
+ // PLL limits +/- 10% around _omega
+ _omegaMin = _omega - 0.005*_omega;
+ _omegaMax = _omega + 0.005*_omega;
+ // PLL gain
+ _gainOmega = 0.0005;
+
+ _symSum = 0;
+ _lastSymSum = 0;
+
+ // Allocate output buffer:
+ _buffer = Buffer(src_cfg.bufferSize()/_corrLen + 1);
+
+ LogMessage msg(LOG_DEBUG);
+ msg << "Config AFSK node: " << std::endl
+ << " input sample rate: " << _sampleRate << " Hz" << std::endl
+ << " samples per symbol: " << _muIncr << std::endl
+ << " symbols per bit: " << _corrLen << std::endl
+ << " symbol rate: " << _symbolRate << " Hz" << std::endl
+ << " bit rate: " << _symbolRate/_corrLen << " baud" << std::endl
+ << " phase incr/symbol: " << float(_omega) << std::endl
+ << " bit mode: " << ((TRANSITION == _mode) ? "transition" : "normal");
+ Logger::get().log(msg);
+
+ // Forward config.
+ this->setConfig(Config(Traits::scalarId, _baud, _buffer.size(), 1));
+}
+
+
+void
+AFSK::process(const Buffer &buffer, bool allow_overwrite)
+{
+ size_t i=0, o=0;
+ while (i=1) && (i= 1) { continue; }
+
+ // Get interpolated symbol
+ float symbol = interpolate(_dl.sub(_dl_idx, 8), _mu); _mu += _muIncr;
+ // store symbol
+ _lastSymSum = _symSum;
+ _symSum -= _symbols[_symbolIdx];
+ _symbols[_symbolIdx] = ( (symbol>=0) ? 1 : -1 );
+ _symSum += _symbols[_symbolIdx];
+ _symbolIdx = ((_symbolIdx+1) % _corrLen);
+ // Advance phase
+ _phase += _omega;
+
+ // Sample bit
+ if (_phase >= 1) {
+ // Modulo "2 pi", phase is defined on the interval [0,1)
+ while (_phase>=1) { _phase -= 1; }
+ // Estimate bit by majority vote on all symbols
+ _lastBits = ((_lastBits<<1) | (_symSum>0));
+ // Put decoded bit in output buffer
+ if (TRANSITION == _mode) {
+ // transition -> 0; no transition -> 1
+ _buffer[o++] = ((_lastBits ^ (_lastBits >> 1) ^ 1) & 1);
+ } else {
+ // mark -> 1, space -> 0
+ _buffer[o++] = _lastBits & 1;
+ }
+ }
+
+ // If there was a symbol transition
+ if (((_lastSymSum < 0) && (_symSum>=0)) || ((_lastSymSum >= 0) && (_symSum<0))) {
+ // Phase correction
+ /**std::cerr << "Transition at phi=" << _phase << std::endl
+ << " update omega from " << _omega << " to "; */
+ // transition at [-pi,0] -> increase omega
+ if (_phase < 0.5) { _omega += _gainOmega*(0.5-_phase); }
+ // transition at [0,pi] -> decrease omega
+ else { _omega -= _gainOmega*(_phase-0.5); }
+ // Limit omega
+ _omega = std::min(_omegaMax, std::max(_omegaMin, _omega));
+ //_phase += _gainOmega*(_phase-0.5);
+ /* std::cerr << _omega << std::endl; */
+ }
+ }
+
+ if (0 < o) { this->send(_buffer.head(o)); }
+}
+
diff --git a/src/afsk.hh b/src/afsk.hh
new file mode 100644
index 0000000..186bcd2
--- /dev/null
+++ b/src/afsk.hh
@@ -0,0 +1,111 @@
+#ifndef __SDR_AFSK_HH__
+#define __SDR_AFSK_HH__
+
+#include "node.hh"
+
+namespace sdr {
+
+/** A simple (Audio) Frequency Shift Keying (AFSK) demodulator.
+ * This node consists of two convolution peak-filters at the mark and space frequencies, a
+ * interpolating sub-sampler to match the baud-rate exactly and a PLL to lock to the symbol
+ * transitions. The node will decode the (A)FSK signal and will send a bit-stream (uint8_t).
+ * @ingroup demodulator */
+class AFSK: public Sink, public Source
+{
+public:
+ /** Possible bit decoding modes. */
+ typedef enum {
+ NORMAL, ///< Normal mode (i.e. mark -> 1, space -> 0).
+ TRANSITION ///< Transition mode (i.e. transition -> 0, no transition -> 1).
+ } Mode;
+
+public:
+ /** Constructs a AFSK node with the specified @c baud rate and @c Fmark, @c Fspace frequencies.
+ * The default valuse corresponds to those used for 1200 baud packet radio. */
+ AFSK(double baud=1200.0, double Fmark=1200.0, double Fspace=2200.0,
+ Mode mode=TRANSITION);
+ /** Destructor. */
+ virtual ~AFSK();
+
+ /** Configures the node. */
+ virtual void config(const Config &src_cfg);
+ /** Processes the given buffer. */
+ virtual void process(const Buffer &buffer, bool allow_overwrite);
+
+protected:
+ /** Performs the convolution filtering of the mark & space frequencies. */
+ inline double _getSymbol() {
+ std::complex markSum(0), spaceSum(0);
+ for (size_t i=0; i<_corrLen; i++) {
+ markSum += _markHist[i];
+ spaceSum += _spaceHist[i];
+ }
+ double f = markSum.real()*markSum.real() +
+ markSum.imag()*markSum.imag() -
+ spaceSum.real()*spaceSum.real() -
+ spaceSum.imag()*spaceSum.imag();
+ return f;
+ }
+
+
+protected:
+ /** The sample rate of the input signal. */
+ float _sampleRate;
+ /** A multiple of the baud rate. */
+ float _symbolRate;
+ /** The baud rate. */
+ float _baud;
+ /** Mark "tone" frequency. */
+ float _Fmark;
+ /** Space "tone" frequency. */
+ float _Fspace;
+ /** Bit encoding mode. */
+ Mode _mode;
+ /** Correlation length, the number of "symbols" per bit. */
+ uint32_t _corrLen;
+ /** The current FIR filter LUT index. */
+ uint32_t _lutIdx;
+ /** Mark frequency FIR filter LUT. */
+ Buffer< std::complex > _markLUT;
+ /** Space frequency FIR filter LUT. */
+ Buffer< std::complex > _spaceLUT;
+
+ /** FIR filter buffer. */
+ Buffer< std::complex > _markHist;
+ /** FIR filter buffer. */
+ Buffer< std::complex > _spaceHist;
+
+ /** Symbol subsampling counter. */
+ float _mu;
+ /** Symbol subsampling. */
+ float _muIncr;
+ /** Delay line for the 8-pole interpolation filter. */
+ Buffer< float > _dl;
+ /** Delay line index. */
+ size_t _dl_idx;
+
+ Buffer _symbols;
+ size_t _symbolIdx;
+ int32_t _symSum;
+ int32_t _lastSymSum;
+
+ /** Last received bits. */
+ uint32_t _lastBits;
+ /** Current PLL phase. */
+ float _phase;
+ /** PLL phase speed. */
+ float _omega;
+ /** Maximum PLL phase speed. */
+ float _omegaMin;
+ /** Minimum PLL phase speed. */
+ float _omegaMax;
+ /** PLL gain. */
+ float _gainOmega;
+
+ /** Output buffer. */
+ Buffer _buffer;
+};
+
+
+}
+#endif // __SDR_AFSK_HH__
diff --git a/src/ax25.cc b/src/ax25.cc
new file mode 100644
index 0000000..ea42d4a
--- /dev/null
+++ b/src/ax25.cc
@@ -0,0 +1,173 @@
+#include "ax25.hh"
+#include "logger.hh"
+#include "traits.hh"
+
+using namespace sdr;
+
+
+static const uint16_t crc_ccitt_table[] = {
+ 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
+ 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
+ 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
+ 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
+ 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
+ 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
+ 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
+ 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
+ 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
+ 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
+ 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
+ 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
+ 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
+ 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
+ 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
+ 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
+ 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
+ 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
+ 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
+ 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
+ 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
+ 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
+ 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
+ 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
+ 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
+ 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
+ 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
+ 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
+ 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
+ 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
+ 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
+ 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
+};
+
+static inline bool check_crc_ccitt(const uint8_t *buf, int cnt)
+{
+ uint32_t crc = 0xffff;
+ for (; cnt > 0; cnt--, buf++) {
+ crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ (*buf)) & 0xff];
+ }
+ return (crc & 0xffff) == 0xf0b8;
+}
+
+
+
+AX25::AX25()
+ : Sink(), Source()
+{
+ // pass...
+}
+
+AX25::~AX25() {
+ // pass...
+}
+
+void
+AX25::config(const Config &src_cfg) {
+ if (! src_cfg.hasType()) { return; }
+ // Check if buffer type matches
+ if (Config::typeId() != src_cfg.type()) {
+ ConfigError err;
+ err << "Can not configure AX25: Invalid type " << src_cfg.type()
+ << ", expected " << Config::typeId();
+ throw err;
+ }
+
+ _bitstream = 0;
+ _bitbuffer = 0;
+ _state = 0;
+ _ptr = _rxbuffer;
+
+ // Allocate output buffer
+ _buffer = Buffer(512);
+
+ LogMessage msg(LOG_DEBUG);
+ msg << "Config AX.25 node.";
+ Logger::get().log(msg);
+
+ // propergate config
+ this->setConfig(Config(Traits::scalarId, 0, 512, 1));
+}
+
+void
+AX25::process(const Buffer &buffer, bool allow_overwrite)
+{
+ for (size_t i=0; i 2)) {
+ *_ptr = 0;
+ if (! check_crc_ccitt(_rxbuffer, _ptr-_rxbuffer)) {
+ LogMessage msg(LOG_DEBUG);
+ msg << "AX.25: Received invalid buffer: " << _rxbuffer;
+ Logger::get().log(msg);
+ } else {
+ bool addrExt;
+ std::string src, dst;
+ int srcSSID, dstSSID;
+ unpackCall(_rxbuffer, dst, dstSSID, addrExt);
+ unpackCall(_rxbuffer+7, src, srcSSID, addrExt);
+ std::cerr << "RX: " << src << "-" << srcSSID
+ << " > " << dst << "-" << dstSSID << std::endl
+ << " " << _rxbuffer+14 << std::endl;
+ memcpy(_buffer.ptr(), _rxbuffer, _ptr-_rxbuffer);
+ this->send(_buffer.head(_ptr-_rxbuffer));
+ }
+ }
+ // Receive data
+ _state = 1;
+ _ptr = _rxbuffer;
+ _bitbuffer = 0x80;
+ continue;
+ }
+
+ // If 7 ones are received in a row -> error, wait or sync byte
+ if ((_bitstream & 0x7f) == 0x7f) { _state = 0; continue; }
+
+ // If state == wait for sync byte -> receive next bit
+ if (!_state) { continue; }
+
+ /* stuffed bit */
+ if ((_bitstream & 0x3f) == 0x3e) { continue; }
+
+ // prepend bit to bitbuffer
+ /// @todo Double check this!!!
+ _bitbuffer |= ((_bitstream & 0x01) << 8);
+
+ // If 8 bits have been received (stored in b8-b1 of _bitbuffer)
+ if (_bitbuffer & 0x01) {
+ // Check for buffer overrun
+ if ((_ptr-_rxbuffer) >= 512) {
+ Logger::get().log(LogMessage(LOG_DEBUG, "AX.25 packet too long."));
+ // Wait for next sync byte
+ _state = 0;
+ continue;
+ }
+
+ // Store received byte and ...
+ *_ptr++ = (_bitbuffer >> 1);
+ // reset bit buffer
+ _bitbuffer = 0x80;
+ continue;
+ }
+
+ // Shift bitbuffer one to the left
+ _bitbuffer >>= 1;
+ }
+}
+
+
+void
+AX25::unpackCall(const uint8_t *buffer, std::string &call, int &ssid, bool &addrExt) {
+ size_t length = 0; call.resize(6);
+ for (size_t i=0; i<6; i++) {
+ call.at(i) = char(buffer[i]>>1);
+ if (' ' != call.at(i)) { length++; }
+ }
+ call.resize(length);
+ ssid = int( (buffer[6] & 0x1f) >> 1);
+ addrExt = !bool(buffer[6] & 0x01);
+}
+
diff --git a/src/ax25.hh b/src/ax25.hh
new file mode 100644
index 0000000..59ce58d
--- /dev/null
+++ b/src/ax25.hh
@@ -0,0 +1,55 @@
+#ifndef __SDR_AX25_HH__
+#define __SDR_AX25_HH__
+
+#include "node.hh"
+
+
+namespace sdr {
+
+/** Decodes AX25 (PacketRadio) messages from a bit stream.
+ *
+ * In conjecture with the (A)FSK demodulator, the AX25 can be used to receive packet radio or APRS
+ * messages. AX25 is usually transmitted as FSK in transition mode, means the bits aren't
+ * encoded by mark & space tones but rather as a transition from mark to space or in reverse. Hence
+ * the FSK node needs to be configured in transition mode.
+ *
+ * The node does not process the actual AX.25 packages, it only checks the frame check sequence and
+ * forwards the AX.25 datagram to all connected sinks on success. The receiving node is responsible
+ * for unpacking and handling the received datagram.
+ *
+ * @ingroup datanode */
+class AX25: public Sink, public Source
+{
+public:
+ /** Constructor. */
+ AX25();
+ /** Destructor. */
+ virtual ~AX25();
+ /** Configures the node. */
+ virtual void config(const Config &src_cfg);
+ /** Processes the bit stream. */
+ virtual void process(const Buffer &buffer, bool allow_overwrite);
+
+ static void unpackCall(const uint8_t *buffer, std::string &call, int &ssid, bool &addrExt);
+
+protected:
+ /** The last bits. */
+ uint32_t _bitstream;
+ /** A buffer of received bits. */
+ uint32_t _bitbuffer;
+ /** The current state. */
+ uint32_t _state;
+
+ /** Message buffer. */
+ uint8_t _rxbuffer[512];
+ /** Insert-pointer to the buffer. */
+ uint8_t *_ptr;
+
+ /** Output buffer. */
+ Buffer _buffer;
+};
+
+}
+
+
+#endif // __SDR_AX25_HH__
diff --git a/src/baseband.hh b/src/baseband.hh
index 11b6842..71696c2 100644
--- a/src/baseband.hh
+++ b/src/baseband.hh
@@ -14,9 +14,9 @@ namespace sdr {
/** This class performs several operations on the complex (integral) input stream, it first filters
* out some part of the input stream using a FIR band pass (band pass is centerred around @c Ff
* with width @c width) then shifts the center frequency @c Fc to 0 and finally sub-samples the
- * resulting stream. This node can be used to select a portion of the input stream and reduce the
- * rate of the stream, allowing for some more expensive operations to be performed on the output
- * stream. */
+ * resulting stream. This node can be used to select a portion of the input spectrum and for the
+ * reduction of the stream rate, allowing for some more expensive operations to be performed on the
+ * output stream. */
template
class IQBaseBand: public Sink< std::complex >, public Source, public FreqShiftBase
{
diff --git a/src/baudot.cc b/src/baudot.cc
new file mode 100644
index 0000000..eda65d9
--- /dev/null
+++ b/src/baudot.cc
@@ -0,0 +1,111 @@
+#include "baudot.hh"
+#include "traits.hh"
+#include "logger.hh"
+
+
+using namespace sdr;
+
+// Baudot code tables
+char Baudot::_letter[32] = { 0, 'E','\n', 'A', ' ', 'S', 'I', 'U','\n', 'D', 'R', 'J', 'N', 'F',
+ 'C', 'K', 'T', 'Z', 'L', 'W', 'H', 'Y', 'P', 'Q', 'O', 'B', 'G', 0,
+ 'M', 'X', 'V', 0};
+char Baudot::_figure[32] = { 0, '3','\n', '-', ' ','\a', '8', '7','\n', '?', '4','\'', ',', '!',
+ ':', '(', '5', '"', ')', '2', '#', '6', '0', '1', '9', '?', '&', 0,
+ '.', '/', ';', 0};
+
+// Some special codes
+#define CHAR_NUL 0
+#define CHAR_STF 27
+#define CHAR_STL 31
+#define CHAR_SPA 4
+
+
+Baudot::Baudot(StopBits stopBits)
+ : Sink(), Source(), _mode(LETTERS)
+{
+ switch (stopBits) {
+ case STOP1:
+ // Pattern xx11 xxxx xxxx xx00
+ // Mask 0011 0000 0000 0011
+ _stopHBits = 2;
+ _bitsPerSymbol = 14;
+ _pattern = 0x3000;
+ _mask = 0x3003;
+ break;
+ case STOP15:
+ // Pattern x11x xxxx xxxx x000
+ // Mask 0110 0000 0000 0111
+ _stopHBits = 3;
+ _bitsPerSymbol = 15;
+ _pattern = 0x6000;
+ _mask = 0x6007;
+ break;
+ case STOP2:
+ // Pattern 11xx xxxx xxxx 0000
+ // Mask 1100 0000 0000 1111
+ _stopHBits = 4;
+ _bitsPerSymbol = 16;
+ _pattern = 0xC000;
+ _mask = 0xC00F;
+ break;
+ }
+}
+
+void
+Baudot::config(const Config &src_cfg) {
+ if (! src_cfg.hasType()) { return; }
+ // Check if buffer type matches
+ if (Config::typeId() != src_cfg.type()) {
+ ConfigError err;
+ err << "Can not configure Baudot: Invalid type " << src_cfg.type()
+ << ", expected " << Config::typeId();
+ throw err;
+ }
+
+ // Init (half) bit stream and counter
+ _bitstream = 0;
+ _bitcount = 0;
+
+ // Compute buffer size.
+ size_t buffer_size = (src_cfg.bufferSize()/(2*_bitsPerSymbol))+1;
+ _buffer = Buffer(buffer_size);
+
+ LogMessage msg(LOG_DEBUG);
+ msg << "Config Baudot node: " << std::endl
+ << " input sample rate: " << src_cfg.sampleRate() << " half-bits/s" << std::endl
+ << " start bits: " << 1 << std::endl
+ << " stop bits: " << float(_stopHBits)/2 << std::endl;
+ Logger::get().log(msg);
+
+ // propergate config
+ this->setConfig(Config(Traits::scalarId, 0, buffer_size, 1));
+}
+
+
+void
+Baudot::process(const Buffer &buffer, bool allow_overwrite)
+{
+ size_t o=0;
+ for (size_t i=0; i>shift)&0x01)<send(_buffer.head(o)); }
+}
diff --git a/src/baudot.hh b/src/baudot.hh
new file mode 100644
index 0000000..e8c7c81
--- /dev/null
+++ b/src/baudot.hh
@@ -0,0 +1,72 @@
+#ifndef __SDR_BAUDOT_HH__
+#define __SDR_BAUDOT_HH__
+
+#include "node.hh"
+#include