diff options
Diffstat (limited to 'gr-digital')
| -rw-r--r-- | gr-digital/grc/digital_block_tree.xml | 1 | ||||
| -rw-r--r-- | gr-digital/grc/digital_simple_correlator.xml | 25 | ||||
| -rw-r--r-- | gr-digital/include/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | gr-digital/include/digital_simple_correlator.h | 107 | ||||
| -rw-r--r-- | gr-digital/lib/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | gr-digital/lib/digital_simple_correlator.cc | 231 | ||||
| -rwxr-xr-x | gr-digital/python/qa_simple_correlator.py | 62 | ||||
| -rw-r--r-- | gr-digital/swig/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | gr-digital/swig/digital_simple_correlator.i | 31 | ||||
| -rw-r--r-- | gr-digital/swig/digital_swig.i | 2 |
10 files changed, 462 insertions, 0 deletions
diff --git a/gr-digital/grc/digital_block_tree.xml b/gr-digital/grc/digital_block_tree.xml index 9efa0d3fb..36827028e 100644 --- a/gr-digital/grc/digital_block_tree.xml +++ b/gr-digital/grc/digital_block_tree.xml @@ -59,6 +59,7 @@ <block>digital_framer_sink_1</block> <block>digital_packet_sink</block> <block>digital_simple_framer</block> + <block>digital_simple_correlator</block> </cat> <cat> <name>Digital Modulators</name> diff --git a/gr-digital/grc/digital_simple_correlator.xml b/gr-digital/grc/digital_simple_correlator.xml new file mode 100644 index 000000000..3b70e59b1 --- /dev/null +++ b/gr-digital/grc/digital_simple_correlator.xml @@ -0,0 +1,25 @@ +<?xml version="1.0"?> +<!-- +################################################### +##Simple Correlator +################################################### + --> +<block> + <name>Simple Correlator</name> + <key>digital_simple_correlator</key> + <import>from gnuradio import digital</import> + <make>digital.simple_correlator($payload_bytesize)</make> + <param> + <name>Payload Byte Size</name> + <key>payload_bytesize</key> + <type>int</type> + </param> + <sink> + <name>in</name> + <type>float</type> + </sink> + <source> + <name>out</name> + <type>byte</type> + </source> +</block> diff --git a/gr-digital/include/CMakeLists.txt b/gr-digital/include/CMakeLists.txt index f863b2875..ad5baec87 100644 --- a/gr-digital/include/CMakeLists.txt +++ b/gr-digital/include/CMakeLists.txt @@ -123,6 +123,7 @@ install(FILES digital_scrambler_bb.h digital_simple_framer.h digital_simple_framer_sync.h + digital_simple_correlator.h DESTINATION ${GR_INCLUDE_DIR}/gnuradio COMPONENT "digital_devel" ) diff --git a/gr-digital/include/digital_simple_correlator.h b/gr-digital/include/digital_simple_correlator.h new file mode 100644 index 000000000..716c6995c --- /dev/null +++ b/gr-digital/include/digital_simple_correlator.h @@ -0,0 +1,107 @@ +/* -*- c++ -*- */ +/* + * Copyright 2004,2013 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3, or (at your option) + * any later version. + * + * GNU Radio 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 General Public License + * along with GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, + * Boston, MA 02110-1301, USA. + */ + +#ifndef INCLUDED_GR_SIMPLE_CORRELATOR_H +#define INCLUDED_GR_SIMPLE_CORRELATOR_H + +#include <digital_api.h> +#include <gr_block.h> + +class digital_simple_correlator; +typedef boost::shared_ptr<digital_simple_correlator> digital_simple_correlator_sptr; + +DIGITAL_API digital_simple_correlator_sptr digital_make_simple_correlator(int payload_bytesize); + +/*! + * \brief inverse of simple_framer (more or less) + * \ingroup sync_blk + */ +class DIGITAL_API digital_simple_correlator : public gr_block +{ + private: + static const int OVERSAMPLE = 8; + enum state_t { ST_LOOKING, ST_UNDER_THRESHOLD, ST_LOCKED }; + + int d_payload_bytesize; + state_t d_state; + unsigned int d_osi; // over sample index [0,OVERSAMPLE-1] + unsigned int d_transition_osi; // first index where Hamming dist < thresh + unsigned int d_center_osi; // center of bit + unsigned long long int d_shift_reg[OVERSAMPLE]; + int d_bblen; // length of bitbuf + unsigned char *d_bitbuf; // demodulated bits + unsigned char *d_pktbuf; // temp packet buf + int d_bbi; // bitbuf index + + static const int AVG_PERIOD = 512; // must be power of 2 (for freq offset correction) + int d_avbi; + float d_avgbuf[AVG_PERIOD]; + float d_avg; + float d_accum; + +#ifdef DEBUG_SIMPLE_CORRELATOR + FILE *d_debug_fp; // binary log file +#endif + + friend GR_CORE_API digital_simple_correlator_sptr + digital_make_simple_correlator(int payload_bytesize); + digital_simple_correlator(int payload_bytesize); + + inline int slice(float x) + { + return x >= d_avg ? 1 : 0; + } + + void update_avg(float x); + + void enter_locked(); + void enter_under_threshold(); + void enter_looking(); + + static int add_index(int a, int b) + { + int t = a + b; + if(t >= OVERSAMPLE) + t -= OVERSAMPLE; + assert(t >= 0 && t < OVERSAMPLE); + return t; + } + + static int sub_index(int a, int b) + { + int t = a - b; + if(t < 0) + t += OVERSAMPLE; + assert(t >= 0 && t < OVERSAMPLE); + return t; + } + + public: + ~digital_simple_correlator(); + + int general_work(int noutput_items, + gr_vector_int &ninput_items, + gr_vector_const_void_star &input_items, + gr_vector_void_star &output_items); +}; + +#endif /* INCLUDED_GR_SIMPLE_CORRELATOR_H */ diff --git a/gr-digital/lib/CMakeLists.txt b/gr-digital/lib/CMakeLists.txt index 6f83ff036..7ac16602c 100644 --- a/gr-digital/lib/CMakeLists.txt +++ b/gr-digital/lib/CMakeLists.txt @@ -136,6 +136,7 @@ list(APPEND gr_digital_sources digital_probe_mpsk_snr_est_c.cc digital_scrambler_bb.cc digital_simple_framer.cc + digital_simple_correlator.cc ) list(APPEND digital_libs diff --git a/gr-digital/lib/digital_simple_correlator.cc b/gr-digital/lib/digital_simple_correlator.cc new file mode 100644 index 000000000..37ef2f1e5 --- /dev/null +++ b/gr-digital/lib/digital_simple_correlator.cc @@ -0,0 +1,231 @@ +/* -*- c++ -*- */ +/* + * Copyright 2004,2010,2013 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3, or (at your option) + * any later version. + * + * GNU Radio 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 General Public License + * along with GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, + * Boston, MA 02110-1301, USA. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <digital_simple_correlator.h> +#include <digital_simple_framer_sync.h> +#include <gr_io_signature.h> +#include <gr_count_bits.h> +#include <assert.h> +#include <stdexcept> +#include <string.h> +#include <cstdio> + +static const int THRESHOLD = 3; + +digital_simple_correlator_sptr +digital_make_simple_correlator(int payload_bytesize) +{ + return gnuradio::get_initial_sptr + (new digital_simple_correlator(payload_bytesize)); +} + +digital_simple_correlator::digital_simple_correlator(int payload_bytesize) + : gr_block("simple_correlator", + gr_make_io_signature(1, 1, sizeof(float)), + gr_make_io_signature(1, 1, sizeof(unsigned char))), + d_payload_bytesize(payload_bytesize), + d_state(ST_LOOKING), d_osi(0), + d_bblen((payload_bytesize + GRSF_PAYLOAD_OVERHEAD) * GRSF_BITS_PER_BYTE), + d_bitbuf(new unsigned char[d_bblen]), + d_pktbuf(new unsigned char[d_bblen/GRSF_BITS_PER_BYTE]), + d_bbi(0) +{ + d_avbi = 0; + d_accum = 0.0; + d_avg = 0.0; + for(int i = 0; i < AVG_PERIOD; i++) + d_avgbuf[i] = 0.0; + +#ifdef DEBUG_SIMPLE_CORRELATOR + d_debug_fp = fopen("corr.log", "w"); +#endif + enter_looking(); +} + +digital_simple_correlator::~digital_simple_correlator() +{ +#ifdef DEBUG_SIMPLE_CORRELATOR + fclose(d_debug_fp); +#endif + delete [] d_bitbuf; + delete [] d_pktbuf; +} + +void +digital_simple_correlator::enter_looking() +{ + fflush(stdout); + // fprintf(stderr, ">>> enter_looking\n"); + d_state = ST_LOOKING; + for(int i = 0; i < OVERSAMPLE; i++) + d_shift_reg[i] = 0; + d_osi = 0; + + d_avbi = 0; + d_avg = d_avg * 0.5; + d_accum = 0; + for(int i = 0; i < AVG_PERIOD; i++) + d_avgbuf[i] = 0.0; +} + +void +digital_simple_correlator::enter_under_threshold() +{ + fflush(stdout); + // fprintf(stderr, ">>> enter_under_threshold\n"); + d_state = ST_UNDER_THRESHOLD; + d_transition_osi = d_osi; +} + +void +digital_simple_correlator::enter_locked() +{ + d_state = ST_LOCKED; + int delta = sub_index(d_osi, d_transition_osi); + d_center_osi = add_index(d_transition_osi, delta/2); + //d_center_osi = add_index(d_center_osi, 3); // FIXME + d_bbi = 0; + fflush(stdout); + // fprintf(stderr, ">>> enter_locked d_center_osi = %d\n", d_center_osi); + + d_avg = std::max(-1.0, std::min(1.0, d_accum * (1.0/AVG_PERIOD))); + // fprintf(stderr, ">>> enter_locked d_avg = %g\n", d_avg); +} + +static void +packit(unsigned char *pktbuf, const unsigned char *bitbuf, int bitcount) +{ + for(int i = 0; i < bitcount; i += 8) { + int t = bitbuf[i+0] & 0x1; + t = (t << 1) | (bitbuf[i+1] & 0x1); + t = (t << 1) | (bitbuf[i+2] & 0x1); + t = (t << 1) | (bitbuf[i+3] & 0x1); + t = (t << 1) | (bitbuf[i+4] & 0x1); + t = (t << 1) | (bitbuf[i+5] & 0x1); + t = (t << 1) | (bitbuf[i+6] & 0x1); + t = (t << 1) | (bitbuf[i+7] & 0x1); + *pktbuf++ = t; + } +} + +void +digital_simple_correlator::update_avg(float x) +{ + d_accum -= d_avgbuf[d_avbi]; + d_avgbuf[d_avbi] = x; + d_accum += x; + d_avbi = (d_avbi + 1) & (AVG_PERIOD-1); +} + +int +digital_simple_correlator::general_work(int noutput_items, + gr_vector_int &ninput_items, + gr_vector_const_void_star &input_items, + gr_vector_void_star &output_items) +{ + const float *in = (const float*)input_items[0]; + unsigned char *out = (unsigned char*)output_items[0]; + + int n = 0; + int nin = ninput_items[0]; + int decision; + int hamming_dist; + +#ifdef DEBUG_SIMPLE_CORRELATOR + struct debug_data { + float raw_data; + float sampled; + float enter_locked; + } debug_data; +#endif + + while(n < nin) { + +#ifdef DEBUG_SIMPLE_CORRELATOR + debug_data.raw_data = in[n]; + debug_data.sampled = 0.0; + debug_data.enter_locked = 0.0; +#endif + + switch(d_state) { + case ST_LOCKED: + if(d_osi == d_center_osi) { + +#ifdef DEBUG_SIMPLE_CORRELATOR + debug_data.sampled = 1.0; +#endif + decision = slice(in[n]); + + d_bitbuf[d_bbi] = decision; + d_bbi++; + if(d_bbi >= d_bblen) { + // printf("got whole packet\n"); + packit(d_pktbuf, d_bitbuf, d_bbi); + //printf("seqno %3d\n", d_pktbuf[0]); + memcpy(out, &d_pktbuf[GRSF_PAYLOAD_OVERHEAD], d_payload_bytesize); + enter_looking(); + consume_each(n + 1); + return d_payload_bytesize; + } + } + break; + + case ST_LOOKING: + case ST_UNDER_THRESHOLD: + update_avg(in[n]); + decision = slice(in[n]); + + d_shift_reg[d_osi] = (d_shift_reg[d_osi] << 1) | decision; + hamming_dist = gr_count_bits64(d_shift_reg[d_osi] ^ GRSF_SYNC); + //fprintf(stderr, "%2d %d\n", hamming_dist, d_osi); + + if(d_state == ST_LOOKING && hamming_dist <= THRESHOLD) { + // We're seeing a good PN code, remember location + enter_under_threshold(); + } + else if(d_state == ST_UNDER_THRESHOLD && hamming_dist > THRESHOLD) { + // no longer seeing good PN code, compute center of goodness + enter_locked(); +#ifdef DEBUG_SIMPLE_CORRELATOR + debug_data.enter_locked = 1.0; +#endif + } + break; + default: + assert(0); + } + +#ifdef DEBUG_SIMPLE_CORRELATOR + fwrite(&debug_data, sizeof(debug_data), 1, d_debug_fp); +#endif + + d_osi = add_index(d_osi, 1); + n++; + } + + consume_each(n); + return 0; +} diff --git a/gr-digital/python/qa_simple_correlator.py b/gr-digital/python/qa_simple_correlator.py new file mode 100755 index 000000000..124201a55 --- /dev/null +++ b/gr-digital/python/qa_simple_correlator.py @@ -0,0 +1,62 @@ +#!/usr/bin/env python +# +# Copyright 2013 Free Software Foundation, Inc. +# +# This file is part of GNU Radio +# +# GNU Radio is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3, or (at your option) +# any later version. +# +# GNU Radio 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 General Public License +# along with GNU Radio; see the file COPYING. If not, write to +# the Free Software Foundation, Inc., 51 Franklin Street, +# Boston, MA 02110-1301, USA. +# + +from gnuradio import gr, gr_unittest +import digital_swig as digital + +class test_simple_correlator(gr_unittest.TestCase): + + def setUp(self): + self.tb = gr.top_block() + + def tearDown(self): + self.tb = None + + def test_00(self): + expected_result = ( + 0x00, 0x11, 0x22, 0x33, + 0x44, 0x55, 0x66, 0x77, + 0x88, 0x99, 0xaa, 0xbb, + 0xcc, 0xdd, 0xee, 0xff) + + # Filter taps to expand the data to oversample by 8 + # Just using a RRC for some basic filter shape + taps = gr.firdes.root_raised_cosine(8, 8, 1.0, 0.5, 21) + + src = gr.vector_source_b(expected_result) + frame = digital.simple_framer(4) + unpack = gr.packed_to_unpacked_bb(1, gr.GR_MSB_FIRST) + expand = gr.interp_fir_filter_fff(8, taps) + b2f = gr.char_to_float() + mult2 = gr.multiply_const_ff(2) + sub1 = gr.add_const_ff(-1) + op = digital.simple_correlator(4) + dst = gr.vector_sink_b() + self.tb.connect(src, frame, unpack, b2f, mult2, sub1, expand) + self.tb.connect(expand, op, dst) + self.tb.run() + result_data = dst.data() + + self.assertEqual(expected_result, result_data) + +if __name__ == '__main__': + gr_unittest.run(test_simple_correlator, "test_simple_correlator.xml") diff --git a/gr-digital/swig/CMakeLists.txt b/gr-digital/swig/CMakeLists.txt index 746bc6111..4107116bc 100644 --- a/gr-digital/swig/CMakeLists.txt +++ b/gr-digital/swig/CMakeLists.txt @@ -176,6 +176,7 @@ install( digital_probe_mpsk_snr_est_c.i digital_scrambler_bb.i digital_simple_framer.i + digital_simple_correlator.i DESTINATION ${GR_INCLUDE_DIR}/gnuradio/swig COMPONENT "digital_swig" ) diff --git a/gr-digital/swig/digital_simple_correlator.i b/gr-digital/swig/digital_simple_correlator.i new file mode 100644 index 000000000..5ad5ca26c --- /dev/null +++ b/gr-digital/swig/digital_simple_correlator.i @@ -0,0 +1,31 @@ +/* -*- c++ -*- */ +/* + * Copyright 2004,2013 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * GNU Radio is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 3, or (at your option) + * any later version. + * + * GNU Radio 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 General Public License + * along with GNU Radio; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 51 Franklin Street, + * Boston, MA 02110-1301, USA. + */ + +GR_SWIG_BLOCK_MAGIC(digital,simple_correlator); + +digital_simple_correlator_sptr digital_make_simple_correlator(int payload_bytesize); + +class digital_simple_correlator : public gr_block +{ + private: + digital_simple_correlator(int payload_bytesize); +}; diff --git a/gr-digital/swig/digital_swig.i b/gr-digital/swig/digital_swig.i index 191076d75..a5f0251a4 100644 --- a/gr-digital/swig/digital_swig.i +++ b/gr-digital/swig/digital_swig.i @@ -81,6 +81,7 @@ enum snr_est_type_t { #include "digital_probe_mpsk_snr_est_c.h" #include "digital_scrambler_bb.h" #include "digital_simple_framer.h" +#include "digital_simple_correlator.h" %} %include "digital_additive_scrambler_bb.i" @@ -125,3 +126,4 @@ enum snr_est_type_t { %include "digital_probe_mpsk_snr_est_c.i" %include "digital_scrambler_bb.i" %include "digital_simple_framer.i" +%include "digital_simple_correlator.i" |