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-rw-r--r--gnuradio-core/src/lib/general/Makefile.am5
-rw-r--r--gnuradio-core/src/lib/general/general.i2
-rw-r--r--gnuradio-core/src/lib/general/gr_constellation_receiver_cb.cc146
-rw-r--r--gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h172
-rw-r--r--gnuradio-core/src/lib/general/gr_constellation_receiver_cb.i54
-rw-r--r--gnuradio-core/src/python/gnuradio/blks2impl/Makefile.am1
-rw-r--r--gnuradio-core/src/python/gnuradio/blks2impl/generic_mod_demod.py328
-rw-r--r--gnuradio-core/src/python/gnuradio/blks2impl/qam.py293
-rw-r--r--gnuradio-core/src/python/gnuradio/blks2impl/qam16.py208
-rw-r--r--gnuradio-core/src/python/gnuradio/blks2impl/qam256.py209
-rw-r--r--gnuradio-core/src/python/gnuradio/blks2impl/qam64.py208
-rw-r--r--gnuradio-core/src/python/gnuradio/blks2impl/qam8.py209
-rw-r--r--gnuradio-examples/python/digital/simple_qam.py64
13 files changed, 979 insertions, 920 deletions
diff --git a/gnuradio-core/src/lib/general/Makefile.am b/gnuradio-core/src/lib/general/Makefile.am
index 3d8a42805..daa3c446e 100644
--- a/gnuradio-core/src/lib/general/Makefile.am
+++ b/gnuradio-core/src/lib/general/Makefile.am
@@ -100,6 +100,7 @@ libgeneral_la_SOURCES = \
gr_math.cc \
gr_misc.cc \
gr_mpsk_receiver_cc.cc \
+ gr_constellation_receiver_cb.cc \
gr_nlog10_ff.cc \
gr_nop.cc \
gr_null_sink.cc \
@@ -256,7 +257,7 @@ grinclude_HEADERS = \
gr_map_bb.h \
gr_math.h \
gr_misc.h \
- gr_mpsk_receiver_cc.h \
+ gr_constellation_receiver_cb.h \
gr_nco.h \
gr_nlog10_ff.h \
gr_nop.h \
@@ -418,7 +419,7 @@ swiginclude_HEADERS = \
gr_lms_dfe_cc.i \
gr_lms_dfe_ff.i \
gr_map_bb.i \
- gr_mpsk_receiver_cc.i \
+ gr_constellation_receiver_cb.i \
gr_nlog10_ff.i \
gr_nop.i \
gr_null_sink.i \
diff --git a/gnuradio-core/src/lib/general/general.i b/gnuradio-core/src/lib/general/general.i
index 68cafce2e..f758211cc 100644
--- a/gnuradio-core/src/lib/general/general.i
+++ b/gnuradio-core/src/lib/general/general.i
@@ -69,6 +69,7 @@
#include <gr_fake_channel_coder_pp.h>
#include <gr_throttle.h>
#include <gr_mpsk_receiver_cc.h>
+#include <gr_constellation_receiver_cb.h>
#include <gr_stream_mux.h>
#include <gr_stream_to_streams.h>
#include <gr_streams_to_stream.h>
@@ -190,6 +191,7 @@
%include "gr_fake_channel_coder_pp.i"
%include "gr_throttle.i"
%include "gr_mpsk_receiver_cc.i"
+%include "gr_constellation_receiver_cb.i"
%include "gr_stream_mux.i"
%include "gr_stream_to_streams.i"
%include "gr_streams_to_stream.i"
diff --git a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.cc b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.cc
new file mode 100644
index 000000000..0a2309ac0
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.cc
@@ -0,0 +1,146 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2005,2006,2007,2010 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 <gr_io_signature.h>
+#include <gr_prefs.h>
+#include <gr_constellation_receiver_cb.h>
+#include <stdexcept>
+#include <gr_math.h>
+#include <gr_expj.h>
+// For debugging
+#include <iostream>
+
+
+#define M_TWOPI (2*M_PI)
+#define VERBOSE_MM 0 // Used for debugging symbol timing loop
+#define VERBOSE_COSTAS 0 // Used for debugging phase and frequency tracking
+
+// Public constructor
+
+gr_constellation_receiver_cb_sptr
+gr_make_constellation_receiver_cb(gr_constellation constell,
+ float alpha, float beta,
+ float fmin, float fmax)
+{
+ return gnuradio::get_initial_sptr(new gr_constellation_receiver_cb (constell,
+ alpha, beta,
+ fmin, fmax));
+}
+
+gr_constellation_receiver_cb::gr_constellation_receiver_cb (gr_constellation constellation,
+ float alpha, float beta,
+ float fmin, float fmax)
+ : gr_block ("constellation_receiver_cb",
+ gr_make_io_signature (1, 1, sizeof (gr_complex)),
+ gr_make_io_signature (1, 1, sizeof (unsigned char))),
+ d_constellation(constellation),
+ d_alpha(alpha), d_beta(beta), d_freq(0), d_max_freq(fmax), d_min_freq(fmin), d_phase(0),
+ d_current_const_point(0)
+{}
+
+void
+gr_constellation_receiver_cb::phase_error_tracking(float phase_error)
+{
+
+ d_freq += d_beta*phase_error; // adjust frequency based on error
+ d_phase += d_freq + d_alpha*phase_error; // adjust phase based on error
+
+ // Make sure we stay within +-2pi
+ while(d_phase > M_TWOPI)
+ d_phase -= M_TWOPI;
+ while(d_phase < -M_TWOPI)
+ d_phase += M_TWOPI;
+
+ // Limit the frequency range
+ d_freq = gr_branchless_clip(d_freq, d_max_freq);
+
+#if VERBOSE_COSTAS
+ printf("cl: phase_error: %f phase: %f freq: %f sample: %f+j%f constellation: %f+j%f\n",
+ phase_error, d_phase, d_freq, sample.real(), sample.imag(),
+ d_constellation.constellation()[d_current_const_point].real(), d_constellation.constellation()[d_current_const_point].imag());
+#endif
+}
+
+int
+gr_constellation_receiver_cb::general_work (int noutput_items,
+ gr_vector_int &ninput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items)
+{
+ const gr_complex *in = (const gr_complex *) input_items[0];
+ unsigned char *out = (unsigned char *) output_items[0];
+
+ int i=0, o=0;
+
+ float phase_error;
+ unsigned int sym_value;
+ gr_complex sample;
+
+ while((o < noutput_items) && (i < ninput_items[0])) {
+ sample = in[i];
+ sym_value = d_constellation.decision_maker(sample);
+ //std::cout << "sym_value: " << sym_value << " sample: " << sample << std::endl;
+ phase_error = -arg(sample*conj(d_constellation.constellation()[sym_value]));
+ phase_error_tracking(phase_error); // corrects phase and frequency offsets
+ out[o++] = sym_value;
+ i++;
+ }
+
+ #if 0
+ printf("ninput_items: %d noutput_items: %d consuming: %d returning: %d\n",
+ ninput_items[0], noutput_items, i, o);
+ #endif
+
+ consume_each(i);
+ return o;
+}
+
+// Base Constellation Class
+
+gr_constellation::gr_constellation (std::vector<gr_complex> constellation) {
+ d_constellation = constellation;
+}
+
+// Chooses points base on shortest distance.
+// Inefficient.
+unsigned int gr_constellation::decision_maker(gr_complex sample)
+{
+ unsigned int table_size = constellation().size();
+ unsigned int min_index = 0;
+ float min_euclid_dist;
+ float euclid_dist;
+
+ min_euclid_dist = norm(sample - constellation()[0]);
+ min_index = 0;
+ for (unsigned int j = 1; j < table_size; j++){
+ euclid_dist = norm(sample - constellation()[j]);
+ if (euclid_dist < min_euclid_dist){
+ min_euclid_dist = euclid_dist;
+ min_index = j;
+ }
+ }
+ return min_index;
+}
diff --git a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h
new file mode 100644
index 000000000..ba38bdad6
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.h
@@ -0,0 +1,172 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004,2007,2010 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_CONSTELLATION_RECEIVER_CB_H
+#define INCLUDED_GR_CONSTELLATION_RECEIVER_CB_H
+
+#include <gr_block.h>
+#include <gr_complex.h>
+#include <math.h>
+#include <fstream>
+
+class gr_constellation
+{
+ public:
+
+ gr_constellation (std::vector<gr_complex> constellation);
+
+ //! Returns the set of points in this constellation.
+ std::vector<gr_complex> constellation() { return d_constellation;}
+
+ //! Returns the constellation point that matches best.
+ //! Also calculates the phase error.
+ unsigned int decision_maker (gr_complex sample);
+
+ unsigned int bits_per_symbol () {
+ return floor(log(d_constellation.size())/log(2));
+ }
+
+ private:
+
+ std::vector<gr_complex> d_constellation;
+};
+
+class gri_mmse_fir_interpolator_cc;
+
+class gr_constellation_receiver_cb;
+typedef boost::shared_ptr<gr_constellation_receiver_cb> gr_constellation_receiver_cb_sptr;
+
+// public constructor
+gr_constellation_receiver_cb_sptr
+gr_make_constellation_receiver_cb (gr_constellation constellation,
+ float alpha, float beta,
+ float fmin, float fmax);
+
+/*!
+ * \brief This block takes care of receiving generic modulated signals through phase, frequency, and symbol
+ * synchronization.
+ * \ingroup sync_blk
+ * \ingroup demod_blk
+ *
+ * This block takes care of receiving generic modulated signals through phase, frequency, and symbol
+ * synchronization. It performs carrier frequency and phase locking as well as symbol timing recovery.
+ *
+ * The phase and frequency synchronization are based on a Costas loop that finds the error of the incoming
+ * signal point compared to its nearest constellation point. The frequency and phase of the NCO are
+ * updated according to this error.
+ *
+ * The symbol synchronization is done using a modified Mueller and Muller circuit from the paper:
+ *
+ * G. R. Danesfahani, T.G. Jeans, "Optimisation of modified Mueller and Muller
+ * algorithm," Electronics Letters, Vol. 31, no. 13, 22 June 1995, pp. 1032 - 1033.
+ *
+ * This circuit interpolates the downconverted sample (using the NCO developed by the Costas loop)
+ * every mu samples, then it finds the sampling error based on this and the past symbols and the decision
+ * made on the samples. Like the phase error detector, there are optimized decision algorithms for BPSK
+ * and QPKS, but 8PSK uses another brute force computation against all possible symbols. The modifications
+ * to the M&M used here reduce self-noise.
+ *
+ */
+
+class gr_constellation_receiver_cb : public gr_block
+{
+ public:
+ int general_work (int noutput_items,
+ gr_vector_int &ninput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items);
+
+
+ // Member function related to the phase/frequency tracking portion of the receiver
+ //! (CL) Returns the value for alpha (the phase gain term)
+ float alpha() const { return d_alpha; }
+
+ //! (CL) Returns the value of beta (the frequency gain term)
+ float beta() const { return d_beta; }
+
+ //! (CL) Returns the current value of the frequency of the NCO in the Costas loop
+ float freq() const { return d_freq; }
+
+ //! (CL) Returns the current value of the phase of the NCO in the Costal loop
+ float phase() const { return d_phase; }
+
+ //! (CL) Sets the value for alpha (the phase gain term)
+ void set_alpha(float alpha) { d_alpha = alpha; }
+
+ //! (CL) Setss the value of beta (the frequency gain term)
+ void set_beta(float beta) { d_beta = beta; }
+
+ //! (CL) Sets the current value of the frequency of the NCO in the Costas loop
+ void set_freq(float freq) { d_freq = freq; }
+
+ //! (CL) Setss the current value of the phase of the NCO in the Costal loop
+ void set_phase(float phase) { d_phase = phase; }
+
+
+protected:
+
+ /*!
+ * \brief Constructor to synchronize incoming M-PSK symbols
+ *
+ * \param constellation constellation of points for generic modulation
+ * \param alpha gain parameter to adjust the phase in the Costas loop (~0.01)
+ * \param beta gain parameter to adjust the frequency in the Costas loop (~alpha^2/4)
+ * \param fmin minimum normalized frequency value the loop can achieve
+ * \param fmax maximum normalized frequency value the loop can achieve
+ *
+ * The constructor also chooses which phase detector and decision maker to use in the work loop based on the
+ * value of M.
+ */
+ gr_constellation_receiver_cb (gr_constellation constellation,
+ float alpha, float beta,
+ float fmin, float fmax);
+
+ void phase_error_tracking(float phase_error);
+
+ private:
+ unsigned int d_M;
+
+ // Members related to carrier and phase tracking
+ float d_alpha;
+ float d_beta;
+ float d_freq, d_max_freq, d_min_freq;
+ float d_phase;
+
+ gr_constellation d_constellation;
+ unsigned int d_current_const_point;
+
+ //! delay line length.
+ static const unsigned int DLLEN = 8;
+
+ //! delay line plus some length for overflow protection
+ gr_complex d_dl[2*DLLEN] __attribute__ ((aligned(8)));
+
+ //! index to delay line
+ unsigned int d_dl_idx;
+
+ friend gr_constellation_receiver_cb_sptr
+ gr_make_constellation_receiver_cb (gr_constellation constell,
+ float alpha, float beta,
+ float fmin, float fmax);
+};
+
+#endif
diff --git a/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.i b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.i
new file mode 100644
index 000000000..b48322f45
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_constellation_receiver_cb.i
@@ -0,0 +1,54 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004 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(gr,constellation_receiver_cb);
+
+%template(gr_complex_vector) std::vector<gr_complex>;
+
+class gr_constellation
+{
+public:
+ gr_constellation (std::vector<gr_complex> constellation);
+ std::vector<gr_complex> constellation();
+ unsigned int decision_maker (gr_complex sample);
+ unsigned int bits_per_symbol ();
+};
+
+gr_constellation_receiver_cb_sptr gr_make_constellation_receiver_cb (gr_constellation constellation,
+ float alpha, float beta,
+ float fmin, float fmax);
+class gr_constellation_receiver_cb : public gr_block
+{
+ private:
+ gr_constellation_receiver_cb (gr_contellation constellation,
+ float alpha, float beta,
+ float fmin, float fmax);
+public:
+ float alpha() const { return d_alpha; }
+ float beta() const { return d_beta; }
+ float freq() const { return d_freq; }
+ float phase() const { return d_phase; }
+ void set_alpha(float alpha) { d_alpha = alpha; }
+ void set_beta(float beta) { d_beta = beta; }
+ void set_freq(float freq) { d_freq = freq; }
+ void set_phase(float phase) { d_phase = phase; }
+};
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/Makefile.am b/gnuradio-core/src/python/gnuradio/blks2impl/Makefile.am
index 7b24fb69d..377b61224 100644
--- a/gnuradio-core/src/python/gnuradio/blks2impl/Makefile.am
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/Makefile.am
@@ -38,6 +38,7 @@ grblkspython_PYTHON = \
filterbank.py \
fm_demod.py \
fm_emph.py \
+ generic_mod_demod.py \
generic_usrp.py \
gmsk.py \
cpm.py \
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/generic_mod_demod.py b/gnuradio-core/src/python/gnuradio/blks2impl/generic_mod_demod.py
new file mode 100644
index 000000000..8bc33d4dc
--- /dev/null
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/generic_mod_demod.py
@@ -0,0 +1,328 @@
+#
+# Copyright 2005,2006,2007,2009 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.
+#
+
+# See gnuradio-examples/python/digital for examples
+
+"""
+differential BPSK modulation and demodulation.
+"""
+
+from gnuradio import gr, gru, modulation_utils
+from math import pi, sqrt
+import psk
+import cmath
+from pprint import pprint
+
+# default values (used in __init__ and add_options)
+_def_samples_per_symbol = 2
+_def_excess_bw = 0.35
+_def_verbose = False
+_def_log = False
+
+# Frequency correction
+_def_freq_alpha = 0.010
+# Symbol timing recovery
+_def_timing_alpha = 0.100
+_def_timing_beta = 0.010
+_def_timing_max_dev = 1.5
+# Fine frequency / Phase correction
+_def_costas_alpha = 0.1
+
+# /////////////////////////////////////////////////////////////////////////////
+# Generic modulator
+# /////////////////////////////////////////////////////////////////////////////
+
+class generic_mod(gr.hier_block2):
+
+ def __init__(self, constellation,
+ samples_per_symbol=_def_samples_per_symbol,
+ excess_bw=_def_excess_bw,
+ verbose=_def_verbose,
+ log=_def_log):
+ """
+ Hierarchical block for RRC-filtered differential generic modulation.
+
+ The input is a byte stream (unsigned char) and the
+ output is the complex modulated signal at baseband.
+
+ @param constellation: determines the modulation type
+ @type constellation: gnuradio.gr.gr_constellation
+ @param samples_per_symbol: samples per baud >= 2
+ @type samples_per_symbol: integer
+ @param excess_bw: Root-raised cosine filter excess bandwidth
+ @type excess_bw: float
+ @param verbose: Print information about modulator?
+ @type verbose: bool
+ @param log: Log modulation data to files?
+ @type log: bool
+ """
+
+ gr.hier_block2.__init__(self, "generic_mod",
+ gr.io_signature(1, 1, gr.sizeof_char), # Input signature
+ gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
+
+ self._constellation = constellation
+ self._samples_per_symbol = samples_per_symbol
+ self._excess_bw = excess_bw
+
+ if not isinstance(self._samples_per_symbol, int) or self._samples_per_symbol < 2:
+ raise TypeError, ("sbp must be an integer >= 2, is %d" % self._samples_per_symbol)
+
+ ntaps = 11 * self._samples_per_symbol
+
+ arity = pow(2,self.bits_per_symbol())
+
+ # turn bytes into k-bit vectors
+ self.bytes2chunks = \
+ gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
+
+ self.diffenc = gr.diff_encoder_bb(arity)
+
+ self.chunks2symbols = gr.chunks_to_symbols_bc(self._constellation.constellation())
+
+ # pulse shaping filter
+ self.rrc_taps = gr.firdes.root_raised_cosine(
+ self._samples_per_symbol, # gain (samples_per_symbol since we're
+ # interpolating by samples_per_symbol)
+ self._samples_per_symbol, # sampling rate
+ 1.0, # symbol rate
+ self._excess_bw, # excess bandwidth (roll-off factor)
+ ntaps)
+ self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol,
+ self.rrc_taps)
+
+ # Connect
+ self.connect(self, self.bytes2chunks, self.diffenc,
+ self.chunks2symbols, self.rrc_filter, self)
+
+ if verbose:
+ self._print_verbage()
+
+ if log:
+ self._setup_logging()
+
+
+ def samples_per_symbol(self):
+ return self._samples_per_symbol
+
+ def bits_per_symbol(self): # static method that's also callable on an instance
+ return self._constellation.bits_per_symbol()
+
+ def add_options(parser):
+ """
+ Adds generic modulation-specific options to the standard parser
+ """
+ parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
+ help="set RRC excess bandwith factor [default=%default]")
+ add_options=staticmethod(add_options)
+
+ def extract_kwargs_from_options(options):
+ """
+ Given command line options, create dictionary suitable for passing to __init__
+ """
+ return {}
+ extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
+
+
+ def _print_verbage(self):
+ print "\nModulator:"
+ print "bits per symbol: %d" % self.bits_per_symbol()
+ print "RRC roll-off factor: %.2f" % self._excess_bw
+
+ def _setup_logging(self):
+ print "Modulation logging turned on."
+ self.connect(self.bytes2chunks,
+ gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
+ self.connect(self.diffenc,
+ gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))
+ self.connect(self.chunks2symbols,
+ gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
+ self.connect(self.rrc_filter,
+ gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
+
+
+# /////////////////////////////////////////////////////////////////////////////
+# Generic demodulator
+#
+# Differentially coherent detection of differentially encoded generically
+# modulated signal.
+# /////////////////////////////////////////////////////////////////////////////
+
+class generic_demod(gr.hier_block2):
+
+ def __init__(self, constellation,
+ samples_per_symbol=_def_samples_per_symbol,
+ excess_bw=_def_excess_bw,
+ freq_alpha=_def_freq_alpha,
+ timing_alpha=_def_timing_alpha,
+ timing_max_dev=_def_timing_max_dev,
+ costas_alpha=_def_costas_alpha,
+ verbose=_def_verbose,
+ log=_def_log):
+ """
+ Hierarchical block for RRC-filtered differential generic demodulation.
+
+ The input is the complex modulated signal at baseband.
+ The output is a stream of bits packed 1 bit per byte (LSB)
+
+ @param constellation: determines the modulation type
+ @type constellation: gnuradio.gr.gr_constellation
+ @param samples_per_symbol: samples per symbol >= 2
+ @type samples_per_symbol: float
+ @param excess_bw: Root-raised cosine filter excess bandwidth
+ @type excess_bw: float
+ @param freq_alpha: loop filter gain for frequency recovery
+ @type freq_alpha: float
+ @param timing_alpha: loop alpha gain for timing recovery
+ @type timing_alpha: float
+ @param timing_max_dev: timing loop maximum rate deviations
+ @type timing_max_dev: float
+ @param costas_alpha: loop filter gain in costas loop
+ @type costas_alphas: float
+ @param verbose: Print information about modulator?
+ @type verbose: bool
+ @param debug: Print modualtion data to files?
+ @type debug: bool
+ """
+
+ gr.hier_block2.__init__(self, "generic_demod",
+ gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
+ gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
+
+ self._constellation = constellation
+ self._samples_per_symbol = samples_per_symbol
+ self._excess_bw = excess_bw
+ self._costas_alpha = costas_alpha
+ self._freq_alpha = freq_alpha
+ self._freq_beta = 0.10*self._freq_alpha
+ self._timing_alpha = timing_alpha
+ self._timing_beta = _def_timing_beta
+ self._timing_max_dev=timing_max_dev
+
+ if not isinstance(self._samples_per_symbol, int) or self._samples_per_symbol < 2:
+ raise TypeError, ("sbp must be an integer >= 2, is %d" % self._samples_per_symbol)
+
+ arity = pow(2,self.bits_per_symbol())
+
+ # Automatic gain control
+ self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
+
+ # Frequency correction
+ self.freq_recov = gr.fll_band_edge_cc(self._samples_per_symbol, self._excess_bw,
+ 11*int(self._samples_per_symbol),
+ self._freq_alpha, self._freq_beta)
+
+ # symbol timing recovery with RRC data filter
+ nfilts = 32
+ ntaps = 11 * int(self._samples_per_symbol*nfilts)
+ taps = gr.firdes.root_raised_cosine(nfilts, nfilts,
+ 1.0/float(self._samples_per_symbol),
+ self._excess_bw, ntaps)
+ self.time_recov = gr.pfb_clock_sync_ccf(self._samples_per_symbol,
+ self._timing_alpha,
+ taps, nfilts, nfilts/2, self._timing_max_dev)
+ self.time_recov.set_beta(self._timing_beta)
+
+ self._costas_beta = 0.25 * self._costas_alpha * self._costas_alpha
+ fmin = -0.25
+ fmax = 0.25
+
+ self.receiver = gr.constellation_receiver_cb(
+ self._constellation,
+ self._costas_alpha, self._costas_beta,
+ fmin, fmax)
+
+ # Do differential decoding based on phase change of symbols
+ self.diffdec = gr.diff_decoder_bb(arity)
+
+ # unpack the k bit vector into a stream of bits
+ self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
+
+ if verbose:
+ self._print_verbage()
+
+ if log:
+ self._setup_logging()
+
+ # Connect and Initialize base class
+ self.connect(self, self.agc, self.freq_recov, self.time_recov, self.receiver,
+ self.diffdec, self.unpack, self)
+
+ def samples_per_symbol(self):
+ return self._samples_per_symbol
+
+ def bits_per_symbol(self): # staticmethod that's also callable on an instance
+ return self._constellation.bits_per_symbol()
+
+ def _print_verbage(self):
+ print "\nDemodulator:"
+ print "bits per symbol: %d" % self.bits_per_symbol()
+ print "RRC roll-off factor: %.2f" % self._excess_bw
+ print "Costas Loop alpha: %.2e" % self._costas_alpha
+ print "Costas Loop beta: %.2e" % self._costas_beta
+ print "M&M mu: %.2f" % self._mm_mu
+ print "M&M mu gain: %.2e" % self._mm_gain_mu
+ print "M&M omega: %.2f" % self._mm_omega
+ print "M&M omega gain: %.2e" % self._mm_gain_omega
+ print "M&M omega limit: %.2f" % self._mm_omega_relative_limit
+
+ def _setup_logging(self):
+ print "Modulation logging turned on."
+ self.connect(self.pre_scaler,
+ gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
+ self.connect(self.agc,
+ gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
+ self.connect(self.rrc_filter,
+ gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
+ self.connect(self.receiver,
+ gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
+ self.connect(self.diffdec,
+ gr.file_sink(gr.sizeof_gr_complex, "rx_diffdec.dat"))
+ self.connect(self.unpack,
+ gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
+
+ def add_options(parser):
+ """
+ Adds generic demodulation-specific options to the standard parser
+ """
+ parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
+ help="set RRC excess bandwith factor [default=%default] (PSK)")
+ parser.add_option("", "--costas-alpha", type="float", default=None,
+ help="set Costas loop alpha value [default=%default] (PSK)")
+ parser.add_option("", "--gain-mu", type="float", default=_def_gain_mu,
+ help="set M&M symbol sync loop gain mu value [default=%default] (GMSK/PSK)")
+ parser.add_option("", "--mu", type="float", default=_def_mu,
+ help="set M&M symbol sync loop mu value [default=%default] (GMSK/PSK)")
+ parser.add_option("", "--omega-relative-limit", type="float", default=_def_omega_relative_limit,
+ help="M&M clock recovery omega relative limit [default=%default] (GMSK/PSK)")
+ add_options=staticmethod(add_options)
+
+ def extract_kwargs_from_options(options):
+ """
+ Given command line options, create dictionary suitable for passing to __init__
+ """
+ return {}
+ extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
+#
+# Add these to the mod/demod registry
+#
+#modulation_utils.add_type_1_mod('dbpsk', dbpsk_mod)
+#modulation_utils.add_type_1_demod('dbpsk', dbpsk_demod)
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/qam.py b/gnuradio-core/src/python/gnuradio/blks2impl/qam.py
index 22b1e1dab..55081bcc0 100644
--- a/gnuradio-core/src/python/gnuradio/blks2impl/qam.py
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/qam.py
@@ -19,95 +19,220 @@
# Boston, MA 02110-1301, USA.
#
-from math import pi, sqrt
-import math
+"""
+QAM modulation and demodulation.
+"""
-# These constellations are generated for Gray coding when symbos [1, ..., m] are used
-# Mapping to Gray coding is therefore unnecessary
+from math import pi, sqrt, log
+from itertools import islice
+
+from gnuradio import gr, gru, modulation_utils
+from gnuradio.blks2impl.generic_mod_demod import generic_mod, generic_demod
+
+
+# default values (used in __init__ and add_options)
+_def_samples_per_symbol = 2
+_def_excess_bw = 0.35
+_def_verbose = False
+_def_log = False
+
+# Frequency correction
+_def_freq_alpha = 0.010
+# Symbol timing recovery
+_def_timing_alpha = 0.100
+_def_timing_beta = 0.010
+_def_timing_max_dev = 1.5
+# Fine frequency / Phase correction
+_def_costas_alpha = 0.1
+
+def is_power_of_four(x):
+ v = log(x)/log(4)
+ return int(v) == v
+
+def get_bit(x, n):
+ """ Get the n'th bit of integer x (from little end)."""
+ return (x&(0x01 << n)) >> n
+
+def get_bits(x, n, k):
+ """ Get the k bits of integer x starting at bit n(from little end)."""
+ # Remove the n smallest bits
+ v = x >> n
+ # Remove all bits bigger than n+k-1
+ return v % pow(2, k)
+
+def gray_codes():
+ """ Generates gray codes."""
+ gcs = [0, 1]
+ yield 0
+ yield 1
+ # The last power of two passed through.
+ lp2 = 2
+ # The next power of two that will be passed through.
+ np2 = 4
+ i = 2
+ while True:
+ if i == lp2:
+ # if i is a power of two then gray number is of form 1100000...
+ result = i + i/2
+ else:
+ # if not we take advantage of the symmetry of all but the last bit
+ # around a power of two.
+ result = gcs[2*lp2-1-i] + lp2
+ gcs.append(result)
+ yield result
+ i += 1
+ if i == np2:
+ lp2 = i
+ np2 = i*2
def make_constellation(m):
- # number of bits/symbol (log2(M))
- k = int(math.log10(m) / math.log10(2.0))
+ """
+ Create a constellation with m possible symbols where m must be
+ a power of 4.
+
+ Points are laid out in a square grid.
- coeff = 1
+ """
+ sqrtm = pow(m, 0.5)
+ if (not isinstance(m, int) or m < 4 or not is_power_of_four(m)):
+ raise ValueError("m must be a power of 4 integer.")
+ # Each symbol holds k bits.
+ k = int(log(m) / log(2.0))
+ # First create a constellation for one quadrant containing m/4 points.
+ # The quadrant has 'side' points along each side of a quadrant.
+ side = int(sqrtm/2)
+ # Number rows and columns using gray codes.
+ gcs = list(islice(gray_codes(), side))
+ # Get inverse gray codes.
+ i_gcs = dict([(v, key) for key, v in enumerate(gcs)])
+ # The distance between points is found.
+ step = 1/(side-0.5)
+
+ gc_to_x = [(i_gcs[gc]+0.5)*step for gc in range(0, side)]
+
+ # Takes the (x, y) location of the point with the quadrant along
+ # with the quadrant number. (x, y) are integers referring to which
+ # point within the quadrant it is.
+ # A complex number representing this location of this point is returned.
+ def get_c(gc_x, gc_y, quad):
+ if quad == 0:
+ return complex(gc_to_x[gc_x], gc_to_x[gc_y])
+ if quad == 1:
+ return complex(-gc_to_x[gc_y], gc_to_x[gc_x])
+ if quad == 2:
+ return complex(-gc_to_x[gc_x], -gc_to_x[gc_y])
+ if quad == 3:
+ return complex(gc_to_x[gc_y], -gc_to_x[gc_x])
+ raise StandardError("Impossible!")
+
+ # First two bits determine quadrant.
+ # Next (k-2)/2 bits determine x position.
+ # Following (k-2)/2 bits determine y position.
+ # How x and y relate to real and imag depends on quadrant (see get_c function).
const_map = []
for i in range(m):
- a = (i&(0x01 << k-1)) >> k-1
- b = (i&(0x01 << k-2)) >> k-2
- bits_i = [((i&(0x01 << k-j-1)) >> k-j-1) for j in range(2, k, 2)]
- bits_q = [((i&(0x01 << k-j-1)) >> k-j-1) for j in range(3, k, 2)]
-
- ss = 0
- ll = len(bits_i)
- for ii in range(ll):
- rr = 0
- for jj in range(ll-ii):
- rr = abs(bits_i[jj] - rr)
- ss += rr*pow(2.0, ii+1)
- re = (2*a-1)*(ss+1)
-
- ss = 0
- ll = len(bits_q)
- for ii in range(ll):
- rr = 0
- for jj in range(ll-ii):
- rr = abs(bits_q[jj] - rr)
- ss += rr*pow(2.0, ii+1)
- im = (2*b-1)*(ss+1)
-
- a = max(re, im)
- if a > coeff:
- coeff = a
- const_map.append(complex(re, im))
-
- norm_map = [complex(i.real/coeff, i.imag/coeff) for i in const_map]
- return norm_map
+ y = get_bits(i, 0, (k-2)/2)
+ x = get_bits(i, (k-2)/2, (k-2)/2)
+ quad = get_bits(i, k-2, 2)
+ const_map.append(get_c(x, y, quad))
+
+ return const_map
-# Common definition of constellations for Tx and Rx
-constellation = {
- 4 : make_constellation(4), # QAM4 (QPSK)
- 8 : make_constellation(8), # QAM8
- 16: make_constellation(16), # QAM16
- 64: make_constellation(64), # QAM64
- 256: make_constellation(256) # QAM256
- }
-
-# -----------------------
-# Do Gray code
-# -----------------------
-# binary to gray coding
-binary_to_gray = {
- 4 : range(4),
- 8 : range(8),
- 16: range(16),
- 64: range(64),
- 256: range(256)
- }
-
-# gray to binary
-gray_to_binary = {
- 4 : range(4),
- 8 : range(8),
- 16: range(16),
- 64: range(64),
- 256: range(256)
- }
-
-# -----------------------
-# Don't Gray code
-# -----------------------
-# identity mapping
-binary_to_ungray = {
- 4 : range(4),
- 8 : range(8),
- 16: range(16),
- 64: range(64)
- }
+
+# /////////////////////////////////////////////////////////////////////////////
+# QAM modulator
+# /////////////////////////////////////////////////////////////////////////////
+
+class qam_mod(generic_mod):
+
+ def __init__(self, m,
+ samples_per_symbol=_def_samples_per_symbol,
+ excess_bw=_def_excess_bw,
+ verbose=_def_verbose,
+ log=_def_log):
+
+ """
+ Hierarchical block for RRC-filtered QAM modulation.
+
+ The input is a byte stream (unsigned char) and the
+ output is the complex modulated signal at baseband.
+
+ @param m: Number of constellation points. Must be a power of four.
+ @type m: integer
+ @param samples_per_symbol: samples per baud >= 2
+ @type samples_per_symbol: integer
+ @param excess_bw: Root-raised cosine filter excess bandwidth
+ @type excess_bw: float
+ @param verbose: Print information about modulator?
+ @type verbose: bool
+ @param log: Log modulation data to files?
+ @type log: bool
+ """
+
+ if not isinstance(m, int) or not is_power_of_four(m):
+ raise ValueError("m must be a power of two integer greater than or equal to 4.")
+
+ points = make_constellation(m)
+ constellation = gr.gr_constellation(points)
+
+ super(qam_mod, self).__init__(constellation, samples_per_symbol,
+ excess_bw, verbose, log)
+
+
+# /////////////////////////////////////////////////////////////////////////////
+# QAM demodulator
+#
+# /////////////////////////////////////////////////////////////////////////////
+
+class qam_demod(generic_demod):
+
+ def __init__(self, m,
+ samples_per_symbol=_def_samples_per_symbol,
+ excess_bw=_def_excess_bw,
+ freq_alpha=_def_freq_alpha,
+ timing_alpha=_def_timing_alpha,
+ timing_max_dev=_def_timing_max_dev,
+ costas_alpha=_def_costas_alpha,
+ verbose=_def_verbose,
+ log=_def_log):
+
+ """
+ Hierarchical block for RRC-filtered QAM modulation.
+
+ The input is a byte stream (unsigned char) and the
+ output is the complex modulated signal at baseband.
+
+ @param m: Number of constellation points. Must be a power of four.
+ @type m: integer
+ @param samples_per_symbol: samples per symbol >= 2
+ @type samples_per_symbol: float
+ @param excess_bw: Root-raised cosine filter excess bandwidth
+ @type excess_bw: float
+ @param freq_alpha: loop filter gain for frequency recovery
+ @type freq_alpha: float
+ @param timing_alpha: loop alpha gain for timing recovery
+ @type timing_alpha: float
+ @param timing_max_dev: timing loop maximum rate deviations
+ @type timing_max_dev: float
+ @param costas_alpha: loop filter gain in costas loop
+ @type costas_alphas: float
+ @param verbose: Print information about modulator?
+ @type verbose: bool
+ @param debug: Print modualtion data to files?
+ @type debug: bool
+ """
+
+ points = make_constellation(m)
+ constellation = gr.gr_constellation(points)
+
+ super(qam_demod, self).__init__(constellation, samples_per_symbol,
+ excess_bw, freq_alpha, timing_alpha,
+ timing_max_dev, costas_alpha, verbose,
+ log)
-# identity mapping
-ungray_to_binary = {
- 4 : range(4),
- 8 : range(8),
- 16: range(16),
- 64: range(64)
- }
+#
+# Add these to the mod/demod registry
+#
+# NOT READY TO BE USED YET -- ENABLE AT YOUR OWN RISK
+#modulation_utils.add_type_1_mod('qam16', qam16_mod)
+#modulation_utils.add_type_1_demod('qam16', qam16_demod)
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/qam16.py b/gnuradio-core/src/python/gnuradio/blks2impl/qam16.py
deleted file mode 100644
index 0bdb9c6fb..000000000
--- a/gnuradio-core/src/python/gnuradio/blks2impl/qam16.py
+++ /dev/null
@@ -1,208 +0,0 @@
-#
-# Copyright 2005,2006,2007 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.
-#
-
-# See gnuradio-examples/python/digital for examples
-
-"""
-QAM16 modulation and demodulation.
-"""
-
-from gnuradio import gr, gru, modulation_utils
-from math import pi, sqrt
-import qam
-import cmath
-from pprint import pprint
-
-# default values (used in __init__ and add_options)
-_def_samples_per_symbol = 2
-_def_excess_bw = 0.35
-_def_gray_code = True
-_def_verbose = False
-_def_log = False
-
-_def_costas_alpha = None
-_def_gain_mu = 0.03
-_def_mu = 0.05
-_def_omega_relative_limit = 0.005
-
-
-# /////////////////////////////////////////////////////////////////////////////
-# QAM16 modulator
-# /////////////////////////////////////////////////////////////////////////////
-
-class qam16_mod(gr.hier_block2):
-
- def __init__(self,
- samples_per_symbol=_def_samples_per_symbol,
- excess_bw=_def_excess_bw,
- gray_code=_def_gray_code,
- verbose=_def_verbose,
- log=_def_log):
-
- """
- Hierarchical block for RRC-filtered QPSK modulation.
-
- The input is a byte stream (unsigned char) and the
- output is the complex modulated signal at baseband.
-
- @param samples_per_symbol: samples per symbol >= 2
- @type samples_per_symbol: integer
- @param excess_bw: Root-raised cosine filter excess bandwidth
- @type excess_bw: float
- @param gray_code: Tell modulator to Gray code the bits
- @type gray_code: bool
- @param verbose: Print information about modulator?
- @type verbose: bool
- @param debug: Print modualtion data to files?
- @type debug: bool
- """
-
- gr.hier_block2.__init__(self, "qam16_mod",
- gr.io_signature(1, 1, gr.sizeof_char), # Input signature
- gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
-
- self._samples_per_symbol = samples_per_symbol
- self._excess_bw = excess_bw
- self._gray_code = gray_code
-
- if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2:
- raise TypeError, ("sbp must be an integer >= 2, is %d" % samples_per_symbol)
-
- ntaps = 11 * samples_per_symbol
-
- arity = pow(2, self.bits_per_symbol())
-
- # turn bytes into k-bit vectors
- self.bytes2chunks = \
- gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
-
- if self._gray_code:
- self.symbol_mapper = gr.map_bb(qam.binary_to_gray[arity])
- else:
- self.symbol_mapper = gr.map_bb(qam.binary_to_ungray[arity])
-
- self.diffenc = gr.diff_encoder_bb(arity)
-
- rot = 1.0
- print "constellation with %d arity" % arity
- rotated_const = map(lambda pt: pt * rot, qam.constellation[arity])
- self.chunks2symbols = gr.chunks_to_symbols_bc(rotated_const)
-
- # pulse shaping filter
- self.rrc_taps = gr.firdes.root_raised_cosine(
- self._samples_per_symbol, # gain (sps since we're interpolating by sps)
- self._samples_per_symbol, # sampling rate
- 1.0, # symbol rate
- self._excess_bw, # excess bandwidth (roll-off factor)
- ntaps)
-
- self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
-
- if verbose:
- self._print_verbage()
-
- if log:
- self._setup_logging()
-
- # Connect
- self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc,
- self.chunks2symbols, self.rrc_filter, self)
-
- def samples_per_symbol(self):
- return self._samples_per_symbol
-
- def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
- return 4
- bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
-
- def _print_verbage(self):
- print "bits per symbol = %d" % self.bits_per_symbol()
- print "Gray code = %s" % self._gray_code
- print "RRS roll-off factor = %f" % self._excess_bw
-
- def _setup_logging(self):
- print "Modulation logging turned on."
- self.connect(self.bytes2chunks,
- gr.file_sink(gr.sizeof_char, "bytes2chunks.dat"))
- self.connect(self.symbol_mapper,
- gr.file_sink(gr.sizeof_char, "graycoder.dat"))
- self.connect(self.diffenc,
- gr.file_sink(gr.sizeof_char, "diffenc.dat"))
- self.connect(self.chunks2symbols,
- gr.file_sink(gr.sizeof_gr_complex, "chunks2symbols.dat"))
- self.connect(self.rrc_filter,
- gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat"))
-
- def add_options(parser):
- """
- Adds QAM modulation-specific options to the standard parser
- """
- parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
- help="set RRC excess bandwith factor [default=%default] (PSK)")
- parser.add_option("", "--no-gray-code", dest="gray_code",
- action="store_false", default=_def_gray_code,
- help="disable gray coding on modulated bits (PSK)")
- add_options=staticmethod(add_options)
-
-
- def extract_kwargs_from_options(options):
- """
- Given command line options, create dictionary suitable for passing to __init__
- """
- return modulation_utils.extract_kwargs_from_options(qam16_mod.__init__,
- ('self',), options)
- extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
-
-
-# /////////////////////////////////////////////////////////////////////////////
-# QAM16 demodulator
-#
-# /////////////////////////////////////////////////////////////////////////////
-
-class qam16_demod(gr.hier_block2):
-
- def __init__(self,
- samples_per_symbol=_def_samples_per_symbol,
- excess_bw=_def_excess_bw,
- costas_alpha=_def_costas_alpha,
- gain_mu=_def_gain_mu,
- mu=_def_mu,
- omega_relative_limit=_def_omega_relative_limit,
- gray_code=_def_gray_code,
- verbose=_def_verbose,
- log=_def_log):
-
- gr.hier_block2.__init__(self, "qam16_demod",
- gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
- gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
- # do this
- pass
-
- def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
- return 4
- bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
-
-#
-# Add these to the mod/demod registry
-#
-# NOT READY TO BE USED YET -- ENABLE AT YOUR OWN RISK
-#modulation_utils.add_type_1_mod('qam16', qam16_mod)
-#modulation_utils.add_type_1_demod('qam16', qam16_demod)
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/qam256.py b/gnuradio-core/src/python/gnuradio/blks2impl/qam256.py
deleted file mode 100644
index fc455f17c..000000000
--- a/gnuradio-core/src/python/gnuradio/blks2impl/qam256.py
+++ /dev/null
@@ -1,209 +0,0 @@
-#
-# Copyright 2005,2006,2007 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.
-#
-
-# See gnuradio-examples/python/digital for examples
-
-"""
-QAM256 modulation and demodulation.
-"""
-
-from gnuradio import gr, gru, modulation_utils
-from math import pi, sqrt
-import qam
-import cmath
-from pprint import pprint
-
-# default values (used in __init__ and add_options)
-_def_samples_per_symbol = 2
-_def_excess_bw = 0.35
-_def_gray_code = True
-_def_verbose = False
-_def_log = False
-
-_def_costas_alpha = None
-_def_gain_mu = 0.03
-_def_mu = 0.05
-_def_omega_relative_limit = 0.005
-
-
-# /////////////////////////////////////////////////////////////////////////////
-# QAM256 modulator
-# /////////////////////////////////////////////////////////////////////////////
-
-class qam256_mod(gr.hier_block2):
-
- def __init__(self,
- samples_per_symbol=_def_samples_per_symbol,
- excess_bw=_def_excess_bw,
- gray_code=_def_gray_code,
- verbose=_def_verbose,
- log=_def_log):
-
- """
- Hierarchical block for RRC-filtered QPSK modulation.
-
- The input is a byte stream (unsigned char) and the
- output is the complex modulated signal at baseband.
-
- @param samples_per_symbol: samples per symbol >= 2
- @type samples_per_symbol: integer
- @param excess_bw: Root-raised cosine filter excess bandwidth
- @type excess_bw: float
- @param gray_code: Tell modulator to Gray code the bits
- @type gray_code: bool
- @param verbose: Print information about modulator?
- @type verbose: bool
- @param debug: Print modualtion data to files?
- @type debug: bool
- """
-
- gr.hier_block2.__init__(self, "qam256_mod",
- gr.io_signature(1, 1, gr.sizeof_char), # Input signature
- gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
-
- self._samples_per_symbol = samples_per_symbol
- self._excess_bw = excess_bw
- self._gray_code = gray_code
-
- if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2:
- raise TypeError, ("sbp must be an integer >= 2, is %d" % samples_per_symbol)
-
- ntaps = 11 * samples_per_symbol
-
- arity = pow(2, self.bits_per_symbol())
-
- # turn bytes into k-bit vectors
- self.bytes2chunks = \
- gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
-
- if self._gray_code:
- self.symbol_mapper = gr.map_bb(qam.binary_to_gray[arity])
- else:
- self.symbol_mapper = gr.map_bb(qam.binary_to_ungray[arity])
-
- self.diffenc = gr.diff_encoder_bb(arity)
-
- rot = 1.0
- print "constellation with %d arity" % arity
- rotated_const = map(lambda pt: pt * rot, qam.constellation[arity])
- self.chunks2symbols = gr.chunks_to_symbols_bc(rotated_const)
-
- # pulse shaping filter
- self.rrc_taps = gr.firdes.root_raised_cosine(
- self._samples_per_symbol, # gain (sps since we're interpolating by sps)
- self._samples_per_symbol, # sampling rate
- 1.0, # symbol rate
- self._excess_bw, # excess bandwidth (roll-off factor)
- ntaps)
-
- self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
-
- if verbose:
- self._print_verbage()
-
- if log:
- self._setup_logging()
-
- # Connect
- self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc,
- self.chunks2symbols, self.rrc_filter, self)
-
- def samples_per_symbol(self):
- return self._samples_per_symbol
-
- def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
- return 8
- bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
-
- def _print_verbage(self):
- print "bits per symbol = %d" % self.bits_per_symbol()
- print "Gray code = %s" % self._gray_code
- print "RRS roll-off factor = %f" % self._excess_bw
-
- def _setup_logging(self):
- print "Modulation logging turned on."
- self.connect(self.bytes2chunks,
- gr.file_sink(gr.sizeof_char, "bytes2chunks.dat"))
- self.connect(self.symbol_mapper,
- gr.file_sink(gr.sizeof_char, "graycoder.dat"))
- self.connect(self.diffenc,
- gr.file_sink(gr.sizeof_char, "diffenc.dat"))
- self.connect(self.chunks2symbols,
- gr.file_sink(gr.sizeof_gr_complex, "chunks2symbols.dat"))
- self.connect(self.rrc_filter,
- gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat"))
-
- def add_options(parser):
- """
- Adds QAM modulation-specific options to the standard parser
- """
- parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
- help="set RRC excess bandwith factor [default=%default] (PSK)")
- parser.add_option("", "--no-gray-code", dest="gray_code",
- action="store_false", default=_def_gray_code,
- help="disable gray coding on modulated bits (PSK)")
- add_options=staticmethod(add_options)
-
-
- def extract_kwargs_from_options(options):
- """
- Given command line options, create dictionary suitable for passing to __init__
- """
- return modulation_utils.extract_kwargs_from_options(qam256_mod.__init__,
- ('self',), options)
- extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
-
-
-# /////////////////////////////////////////////////////////////////////////////
-# QAM256 demodulator
-#
-# /////////////////////////////////////////////////////////////////////////////
-
-class qam256_demod(gr.hier_block2):
-
- def __init__(self,
- samples_per_symbol=_def_samples_per_symbol,
- excess_bw=_def_excess_bw,
- costas_alpha=_def_costas_alpha,
- gain_mu=_def_gain_mu,
- mu=_def_mu,
- omega_relative_limit=_def_omega_relative_limit,
- gray_code=_def_gray_code,
- verbose=_def_verbose,
- log=_def_log):
-
- gr.hier_block2.__init__(self, "qam256_demod",
- gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
- gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
-
- # do this
- pass
-
- def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
- return 8
- bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
-
-#
-# Add these to the mod/demod registry
-#
-# NOT READY TO BE USED YET -- ENABLE AT YOUR OWN RISK
-#modulation_utils.add_type_1_mod('qam256', qam256_mod)
-#modulation_utils.add_type_1_demod('qam256', qam256_demod)
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/qam64.py b/gnuradio-core/src/python/gnuradio/blks2impl/qam64.py
deleted file mode 100644
index 5509f3745..000000000
--- a/gnuradio-core/src/python/gnuradio/blks2impl/qam64.py
+++ /dev/null
@@ -1,208 +0,0 @@
-#
-# Copyright 2005,2006,2007 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.
-#
-
-# See gnuradio-examples/python/digital for examples
-
-"""
-differential QPSK modulation and demodulation.
-"""
-
-from gnuradio import gr, gru, modulation_utils
-from math import pi, sqrt
-import qam
-import cmath
-from pprint import pprint
-
-# default values (used in __init__ and add_options)
-_def_samples_per_symbol = 2
-_def_excess_bw = 0.35
-_def_gray_code = True
-_def_verbose = False
-_def_log = False
-
-_def_costas_alpha = None
-_def_gain_mu = 0.03
-_def_mu = 0.05
-_def_omega_relative_limit = 0.005
-
-
-# /////////////////////////////////////////////////////////////////////////////
-# QAM64 modulator
-# /////////////////////////////////////////////////////////////////////////////
-
-class qam64_mod(gr.hier_block2):
-
- def __init__(self,
- samples_per_symbol=_def_samples_per_symbol,
- excess_bw=_def_excess_bw,
- gray_code=_def_gray_code,
- verbose=_def_verbose,
- log=_def_log):
-
- """
- Hierarchical block for RRC-filtered QPSK modulation.
-
- The input is a byte stream (unsigned char) and the
- output is the complex modulated signal at baseband.
-
- @param samples_per_symbol: samples per symbol >= 2
- @type samples_per_symbol: integer
- @param excess_bw: Root-raised cosine filter excess bandwidth
- @type excess_bw: float
- @param gray_code: Tell modulator to Gray code the bits
- @type gray_code: bool
- @param verbose: Print information about modulator?
- @type verbose: bool
- @param debug: Print modualtion data to files?
- @type debug: bool
- """
-
- gr.hier_block2.__init__(self, "qam64_mod",
- gr.io_signature(1, 1, gr.sizeof_char), # Input signature
- gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
- self._samples_per_symbol = samples_per_symbol
- self._excess_bw = excess_bw
- self._gray_code = gray_code
-
- if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2:
- raise TypeError, ("sbp must be an integer >= 2, is %d" % samples_per_symbol)
-
- ntaps = 11 * samples_per_symbol
-
- arity = pow(2, self.bits_per_symbol())
-
- # turn bytes into k-bit vectors
- self.bytes2chunks = \
- gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
-
- if self._gray_code:
- self.symbol_mapper = gr.map_bb(qam.binary_to_gray[arity])
- else:
- self.symbol_mapper = gr.map_bb(qam.binary_to_ungray[arity])
-
- self.diffenc = gr.diff_encoder_bb(arity)
-
- rot = 1.0
- print "constellation with %d arity" % arity
- rotated_const = map(lambda pt: pt * rot, qam.constellation[arity])
- self.chunks2symbols = gr.chunks_to_symbols_bc(rotated_const)
-
- # pulse shaping filter
- self.rrc_taps = gr.firdes.root_raised_cosine(
- self._samples_per_symbol, # gain (sps since we're interpolating by sps)
- self._samples_per_symbol, # sampling rate
- 1.0, # symbol rate
- self._excess_bw, # excess bandwidth (roll-off factor)
- ntaps)
-
- self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
-
- if verbose:
- self._print_verbage()
-
- if log:
- self._setup_logging()
-
- # Connect
- self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc,
- self.chunks2symbols, self.rrc_filter, self)
-
- def samples_per_symbol(self):
- return self._samples_per_symbol
-
- def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
- return 6
- bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
-
- def _print_verbage(self):
- print "bits per symbol = %d" % self.bits_per_symbol()
- print "Gray code = %s" % self._gray_code
- print "RRS roll-off factor = %f" % self._excess_bw
-
- def _setup_logging(self):
- print "Modulation logging turned on."
- self.connect(self.bytes2chunks,
- gr.file_sink(gr.sizeof_char, "bytes2chunks.dat"))
- self.connect(self.symbol_mapper,
- gr.file_sink(gr.sizeof_char, "graycoder.dat"))
- self.connect(self.diffenc,
- gr.file_sink(gr.sizeof_char, "diffenc.dat"))
- self.connect(self.chunks2symbols,
- gr.file_sink(gr.sizeof_gr_complex, "chunks2symbols.dat"))
- self.connect(self.rrc_filter,
- gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat"))
-
- def add_options(parser):
- """
- Adds QAM modulation-specific options to the standard parser
- """
- parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
- help="set RRC excess bandwith factor [default=%default] (PSK)")
- parser.add_option("", "--no-gray-code", dest="gray_code",
- action="store_false", default=_def_gray_code,
- help="disable gray coding on modulated bits (PSK)")
- add_options=staticmethod(add_options)
-
-
- def extract_kwargs_from_options(options):
- """
- Given command line options, create dictionary suitable for passing to __init__
- """
- return modulation_utils.extract_kwargs_from_options(qam64_mod.__init__,
- ('self',), options)
- extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
-
-
-# /////////////////////////////////////////////////////////////////////////////
-# QAM16 demodulator
-#
-# /////////////////////////////////////////////////////////////////////////////
-
-class qam64_demod(gr.hier_block2):
-
- def __init__(self,
- samples_per_symbol=_def_samples_per_symbol,
- excess_bw=_def_excess_bw,
- costas_alpha=_def_costas_alpha,
- gain_mu=_def_gain_mu,
- mu=_def_mu,
- omega_relative_limit=_def_omega_relative_limit,
- gray_code=_def_gray_code,
- verbose=_def_verbose,
- log=_def_log):
-
- gr.hier_block2.__init__(self, "qam64_demod",
- gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
- gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
-
- # do this
- pass
-
- def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
- return 6
- bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
-
-#
-# Add these to the mod/demod registry
-#
-# NOT READY TO BE USED YET -- ENABLE AT YOUR OWN RISK
-#modulation_utils.add_type_1_mod('qam64', qam64_mod)
-#modulation_utils.add_type_1_demod('qam16', qam16_demod)
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/qam8.py b/gnuradio-core/src/python/gnuradio/blks2impl/qam8.py
deleted file mode 100644
index 6a7b35597..000000000
--- a/gnuradio-core/src/python/gnuradio/blks2impl/qam8.py
+++ /dev/null
@@ -1,209 +0,0 @@
-#
-# Copyright 2005,2006,2007 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.
-#
-
-# See gnuradio-examples/python/digital for examples
-
-"""
-QAM8 modulation and demodulation.
-"""
-
-from gnuradio import gr, gru, modulation_utils
-from math import pi, sqrt
-import qam
-import cmath
-from pprint import pprint
-
-# default values (used in __init__ and add_options)
-_def_samples_per_symbol = 2
-_def_excess_bw = 0.35
-_def_gray_code = True
-_def_verbose = False
-_def_log = False
-
-_def_costas_alpha = None
-_def_gain_mu = 0.03
-_def_mu = 0.05
-_def_omega_relative_limit = 0.005
-
-
-# /////////////////////////////////////////////////////////////////////////////
-# QAM8 modulator
-# /////////////////////////////////////////////////////////////////////////////
-
-class qam8_mod(gr.hier_block2):
-
- def __init__(self,
- samples_per_symbol=_def_samples_per_symbol,
- excess_bw=_def_excess_bw,
- gray_code=_def_gray_code,
- verbose=_def_verbose,
- log=_def_log):
-
- """
- Hierarchical block for RRC-filtered QPSK modulation.
-
- The input is a byte stream (unsigned char) and the
- output is the complex modulated signal at baseband.
-
- @param samples_per_symbol: samples per symbol >= 2
- @type samples_per_symbol: integer
- @param excess_bw: Root-raised cosine filter excess bandwidth
- @type excess_bw: float
- @param gray_code: Tell modulator to Gray code the bits
- @type gray_code: bool
- @param verbose: Print information about modulator?
- @type verbose: bool
- @param debug: Print modualtion data to files?
- @type debug: bool
- """
-
- gr.hier_block2.__init__(self, "qam8_mod",
- gr.io_signature(1, 1, gr.sizeof_char), # Input signature
- gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
-
- self._samples_per_symbol = samples_per_symbol
- self._excess_bw = excess_bw
- self._gray_code = gray_code
-
- if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2:
- raise TypeError, ("sbp must be an integer >= 2, is %d" % samples_per_symbol)
-
- ntaps = 11 * samples_per_symbol
-
- arity = pow(2, self.bits_per_symbol())
-
- # turn bytes into k-bit vectors
- self.bytes2chunks = \
- gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
-
- if self._gray_code:
- self.symbol_mapper = gr.map_bb(qam.binary_to_gray[arity])
- else:
- self.symbol_mapper = gr.map_bb(qam.binary_to_ungray[arity])
-
- self.diffenc = gr.diff_encoder_bb(arity)
-
- rot = 1.0
- print "constellation with %d arity" % arity
- rotated_const = map(lambda pt: pt * rot, qam.constellation[arity])
- self.chunks2symbols = gr.chunks_to_symbols_bc(rotated_const)
-
- # pulse shaping filter
- self.rrc_taps = gr.firdes.root_raised_cosine(
- self._samples_per_symbol, # gain (sps since we're interpolating by sps)
- self._samples_per_symbol, # sampling rate
- 1.0, # symbol rate
- self._excess_bw, # excess bandwidth (roll-off factor)
- ntaps)
-
- self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
-
- if verbose:
- self._print_verbage()
-
- if log:
- self._setup_logging()
-
- # Connect
- self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc,
- self.chunks2symbols, self.rrc_filter, self)
-
- def samples_per_symbol(self):
- return self._samples_per_symbol
-
- def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
- return 3
- bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
-
- def _print_verbage(self):
- print "bits per symbol = %d" % self.bits_per_symbol()
- print "Gray code = %s" % self._gray_code
- print "RRS roll-off factor = %f" % self._excess_bw
-
- def _setup_logging(self):
- print "Modulation logging turned on."
- self.connect(self.bytes2chunks,
- gr.file_sink(gr.sizeof_char, "bytes2chunks.dat"))
- self.connect(self.symbol_mapper,
- gr.file_sink(gr.sizeof_char, "graycoder.dat"))
- self.connect(self.diffenc,
- gr.file_sink(gr.sizeof_char, "diffenc.dat"))
- self.connect(self.chunks2symbols,
- gr.file_sink(gr.sizeof_gr_complex, "chunks2symbols.dat"))
- self.connect(self.rrc_filter,
- gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat"))
-
- def add_options(parser):
- """
- Adds QAM modulation-specific options to the standard parser
- """
- parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
- help="set RRC excess bandwith factor [default=%default] (PSK)")
- parser.add_option("", "--no-gray-code", dest="gray_code",
- action="store_false", default=_def_gray_code,
- help="disable gray coding on modulated bits (PSK)")
- add_options=staticmethod(add_options)
-
-
- def extract_kwargs_from_options(options):
- """
- Given command line options, create dictionary suitable for passing to __init__
- """
- return modulation_utils.extract_kwargs_from_options(qam8_mod.__init__,
- ('self',), options)
- extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
-
-
-# /////////////////////////////////////////////////////////////////////////////
-# QAM8 demodulator
-#
-# /////////////////////////////////////////////////////////////////////////////
-
-class qam8_demod(gr.hier_block2):
-
- def __init__(self,
- samples_per_symbol=_def_samples_per_symbol,
- excess_bw=_def_excess_bw,
- costas_alpha=_def_costas_alpha,
- gain_mu=_def_gain_mu,
- mu=_def_mu,
- omega_relative_limit=_def_omega_relative_limit,
- gray_code=_def_gray_code,
- verbose=_def_verbose,
- log=_def_log):
-
- gr.hier_block2.__init__(self, "qam8_demod",
- gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
- gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
-
- # do this
- pass
-
- def bits_per_symbol(self=None): # staticmethod that's also callable on an instance
- return 3
- bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
-
-#
-# Add these to the mod/demod registry
-#
-# NOT READY TO BE USED YET -- ENABLE AT YOUR OWN RISK
-modulation_utils.add_type_1_mod('qam8', qam8_mod)
-#modulation_utils.add_type_1_demod('qam8', qam8_demod)
diff --git a/gnuradio-examples/python/digital/simple_qam.py b/gnuradio-examples/python/digital/simple_qam.py
new file mode 100644
index 000000000..dee57baeb
--- /dev/null
+++ b/gnuradio-examples/python/digital/simple_qam.py
@@ -0,0 +1,64 @@
+
+from gnuradio import gr, blks2, packet_utils
+
+# Some constants
+NOISE_VOLTAGE = 0
+FREQUENCY_OFFSET = 0
+TIMING_OFFSET = 1.0
+SAMPLES_PER_SYMBOL = 2
+GAIN = 1.0
+SW_DECIM = 1
+BAND_MIDPOINT = 1.0
+BAND_WIDTH = 0.5
+
+# Modulation/Demodulation methods
+modulator = blks2.qam_mod(4, SAMPLES_PER_SYMBOL)
+demodulator = blks2.qam_demod(4, SAMPLES_PER_SYMBOL)
+
+#Transmission Blocks
+packet_transmitter = blks2.mod_pkts(modulator, access_code=None, msgq_limit=4,
+ pad_for_usrp=True)
+# Channel
+channel = gr.channel_model(NOISE_VOLTAGE, FREQUENCY_OFFSET, TIMING_OFFSET)
+# Receiver Blocks
+chan_coeffs = gr.firdes.low_pass(GAIN, SW_DECIM * SAMPLES_PER_SYMBOL,
+ BAND_MIDPOINT, BAND_WIDTH, gr.firdes.WIN_HANN)
+channel_filter = gr.fft_filter_ccc(SW_DECIM, chan_coeffs)
+packet_receiver = blks2.demod_pkts(demodulator, access_code=None, callback=None,
+ threshold=-1)
+# Put it all together and start it up (although nothing will be done
+# until we send some packets).
+tb = gr.top_block()
+tb.connect(packet_transmitter, channel, channel_filter,
+ packet_receiver)
+tb.start()
+
+# The queue into which recieved packets are placed
+pkq = packet_receiver._rcvd_pktq
+
+# The function to create a packet and place it in a queue to be sent.
+sender = packet_transmitter.send_pkt
+
+# Some some packets (The second will not be recieved because it gets cut off
+# before it can finish. I think this occurs during modulation.)
+sender('hello1')
+sender('hello2')
+sender('hello3')
+sender('hello4')
+sender('hello5')
+sender('hello6')
+sender('hello7')
+sender('world')
+sender(eof=True)
+
+# Wait for all the packets to get sent and received.
+tb.wait()
+
+# Check how many messages have been received and print them.
+cnt = pkq.count()
+print('There are %s messages' % cnt)
+for a in range(0, cnt):
+ msg = pkq.delete_head()
+ ok, payload = packet_utils.unmake_packet(msg.to_string(), int(msg.arg1()))
+ print("Message %s is %s" % (a, payload))
+