From 016fccfd58c68ad52fd845419f57e03370851b1f Mon Sep 17 00:00:00 2001
From: Tom <trondeau@vt.edu>
Date: Fri, 9 Oct 2009 18:21:08 -0700
Subject: Adding new DBPSK block with new PFB clock recovery alg.
---
.../src/python/gnuradio/blks2impl/dbpsk2.py | 353 +++++++++++++++++++++
1 file changed, 353 insertions(+)
create mode 100644 gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
(limited to 'gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py')
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
new file mode 100644
index 0000000000..e9e3e965fe
--- /dev/null
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
@@ -0,0 +1,353 @@
+#
+# 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 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_gray_code = True
+_def_verbose = False
+_def_log = False
+
+_def_costas_alpha = 0.1
+_def_timing_alpha = None
+_def_timing_beta = None
+_def_timing_max_dev = 1.5
+
+
+# /////////////////////////////////////////////////////////////////////////////
+# DBPSK modulator
+# /////////////////////////////////////////////////////////////////////////////
+
+class dbpsk2_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 differential BPSK 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 baud >= 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 log: Log modulation data to files?
+ @type log: bool
+ """
+
+ gr.hier_block2.__init__(self, "dbpsk_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(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)
+
+ if self._gray_code:
+ self.symbol_mapper = gr.map_bb(psk.binary_to_gray[arity])
+ else:
+ self.symbol_mapper = gr.map_bb(psk.binary_to_ungray[arity])
+
+ self.diffenc = gr.diff_encoder_bb(arity)
+
+ self.chunks2symbols = gr.chunks_to_symbols_bc(psk.constellation[arity])
+
+ # 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.symbol_mapper, 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=None): # static method that's also callable on an instance
+ return 1
+ bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
+
+ def add_options(parser):
+ """
+ Adds DBPSK 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]")
+ parser.add_option("", "--no-gray-code", dest="gray_code",
+ action="store_false", default=True,
+ 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(dbpsk2_mod.__init__,
+ ('self',), options)
+ 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 "Gray code: %s" % self._gray_code
+ 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.symbol_mapper,
+ gr.file_sink(gr.sizeof_char, "tx_graycoder.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"))
+
+
+# /////////////////////////////////////////////////////////////////////////////
+# DBPSK demodulator
+#
+# Differentially coherent detection of differentially encoded BPSK
+# /////////////////////////////////////////////////////////////////////////////
+
+class dbpsk2_demod(gr.hier_block2):
+
+ def __init__(self,
+ samples_per_symbol=_def_samples_per_symbol,
+ excess_bw=_def_excess_bw,
+ costas_alpha=_def_costas_alpha,
+ timing_alpha=_def_timing_alpha,
+ timing_max_dev=_def_timing_max_dev,
+ gray_code=_def_gray_code,
+ verbose=_def_verbose,
+ log=_def_log):
+ """
+ Hierarchical block for RRC-filtered differential BPSK demodulation
+
+ The input is the complex modulated signal at baseband.
+ The output is a stream of bits packed 1 bit per byte (LSB)
+
+ @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 costas_alpha: loop filter gain
+ @type costas_alpha: float
+ @param timing_alpha: timing loop alpha gain
+ @type timing_alpha: float
+ @param timing_max: timing loop maximum rate deviations
+ @type timing_max: 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, "dbpsk2_demod",
+ gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
+ gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
+
+ self._samples_per_symbol = samples_per_symbol
+ self._excess_bw = excess_bw
+ self._costas_alpha = costas_alpha
+ self._timing_alpha = timing_alpha
+ self._timing_beta = _def_timing_alpha
+ self._timing_max_dev=timing_max_dev
+ self._gray_code = gray_code
+
+ if samples_per_symbol < 2:
+ raise TypeError, "samples_per_symbol must be >= 2, is %r" % (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)
+ self.agc = gr.feedforward_agc_cc(16, 1.0)
+
+ self._costas_beta = 0.25 * self._costas_alpha * self._costas_alpha
+ fmin = -0.25
+ fmax = 0.25
+
+ self.clock_recov = gr.costas_loop_cc(self._costas_alpha,
+ self._costas_beta,
+ fmax, fmin, arity)
+
+ # symbol clock recovery
+ if not self._timing_alpha:
+ self._timing_alpha = 2
+ self._timing_beta = 0.020
+
+ # RRC data filter
+ nfilts = 8
+ ntaps = 11 * samples_per_symbol*nfilts
+ taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 0.25, 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)
+
+ # Do differential decoding based on phase change of symbols
+ self.diffdec = gr.diff_phasor_cc()
+
+ # find closest constellation point
+ rot = 1
+ rotated_const = map(lambda pt: pt * rot, psk.constellation[arity])
+ self.slicer = gr.constellation_decoder_cb(rotated_const, range(arity))
+
+ if self._gray_code:
+ self.symbol_mapper = gr.map_bb(psk.gray_to_binary[arity])
+ else:
+ self.symbol_mapper = gr.map_bb(psk.ungray_to_binary[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.clock_recov,
+ self.time_recov,
+ self.diffdec, self.slicer, self.symbol_mapper, self.unpack, 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 1
+ bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM
+
+ def _print_verbage(self):
+ print "\nDemodulator:"
+ print "bits per symbol: %d" % self.bits_per_symbol()
+ print "Gray code: %s" % self._gray_code
+ print "RRC roll-off factor: %.2f" % self._excess_bw
+ print "Costas Loop alpha: %.2f" % self._costas_alpha
+ print "Costas Loop beta: %.2f" % self._costas_beta
+ print "Timing alpha gain: %.2f" % self._timing_alpha
+ print "Timing beta gain: %.2f" % self._timing_beta
+ print "Timing max dev: %.2f" % self._timing_max_dev
+
+ 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.slicer,
+ gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
+ self.connect(self.symbol_mapper,
+ gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
+ self.connect(self.unpack,
+ gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
+
+ def add_options(parser):
+ """
+ Adds DBPSK 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("", "--no-gray-code", dest="gray_code",
+ action="store_false", default=_def_gray_code,
+ help="disable gray coding on modulated bits (PSK)")
+ parser.add_option("", "--costas-alpha", type="float", default=None,
+ help="set Costas loop alpha value [default=%default] (PSK)")
+ parser.add_option("", "--gain-alpha", type="float", default=_def_timing_alpha,
+ help="set timing symbol sync loop gain alpha value [default=%default] (GMSK/PSK)")
+ parser.add_option("", "--gain-beta", type="float", default=_def_timing_beta,
+ help="set timing symbol sync loop gain beta value [default=%default] (GMSK/PSK)")
+ parser.add_option("", "--timing-max-dev", type="float", default=_def_timing_max_dev,
+ help="set timing symbol sync loop maximum deviation [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 modulation_utils.extract_kwargs_from_options(
+ dbpsk2_demod.__init__, ('self',), options)
+ extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
+#
+# Add these to the mod/demod registry
+#
+modulation_utils.add_type_1_mod('dbpsk2', dbpsk2_mod)
+modulation_utils.add_type_1_demod('dbpsk2', dbpsk2_demod)
--
cgit v1.2.3
From cd963d806b7f324fd845c7b51ef20985000b774c Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Mon, 12 Oct 2009 13:26:00 -0400
Subject: Working DBPSK implementation with new PFB clock recovery block. The
feedforward AGC wasn't playing nicely, the frequency aquistion range was
increased to swing half the sample rate in either direction, and the number
of filter phases to use was increased to 32.
---
gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
(limited to 'gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py')
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
index e9e3e965fe..e2bce5ff08 100644
--- a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
@@ -230,12 +230,13 @@ class dbpsk2_demod(gr.hier_block2):
arity = pow(2,self.bits_per_symbol())
# Automatic gain control
- #self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
- self.agc = gr.feedforward_agc_cc(16, 1.0)
+ self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
+ #self.agc = gr.feedforward_agc_cc(16, 1.0)
self._costas_beta = 0.25 * self._costas_alpha * self._costas_alpha
- fmin = -0.25
- fmax = 0.25
+ # Allow a frequency swing of +/- half of the sample rate
+ fmin = -0.5
+ fmax = 0.5
self.clock_recov = gr.costas_loop_cc(self._costas_alpha,
self._costas_beta,
@@ -247,9 +248,9 @@ class dbpsk2_demod(gr.hier_block2):
self._timing_beta = 0.020
# RRC data filter
- nfilts = 8
+ nfilts = 32
ntaps = 11 * samples_per_symbol*nfilts
- taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 0.25, self._excess_bw, ntaps)
+ 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)
@@ -279,7 +280,7 @@ class dbpsk2_demod(gr.hier_block2):
# Connect and Initialize base class
self.connect(self, self.agc,
- #self.clock_recov,
+ self.clock_recov,
self.time_recov,
self.diffdec, self.slicer, self.symbol_mapper, self.unpack, self)
--
cgit v1.2.3
From 45d5eda3eb2069e963f913570e3de80184e0e6ce Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Mon, 12 Oct 2009 16:03:47 -0400
Subject: Minor fixes for logging.
---
gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
(limited to 'gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py')
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
index e2bce5ff08..c56b598fab 100644
--- a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
@@ -278,7 +278,7 @@ class dbpsk2_demod(gr.hier_block2):
if log:
self._setup_logging()
- # Connect and Initialize base class
+ # Connect
self.connect(self, self.agc,
self.clock_recov,
self.time_recov,
@@ -310,8 +310,10 @@ class dbpsk2_demod(gr.hier_block2):
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.clock_recov,
+ gr.file_sink(gr.sizeof_gr_complex, "rx_clock_recov.dat"))
+ self.connect(self.time_recov,
+ gr.file_sink(gr.sizeof_gr_complex, "rx_time_recov.dat"))
self.connect(self.diffdec,
gr.file_sink(gr.sizeof_gr_complex, "rx_diffdec.dat"))
self.connect(self.slicer,
--
cgit v1.2.3
From 6f6b022977a74596c19ae1b0748010a86abdfed2 Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Mon, 12 Oct 2009 18:36:55 -0400
Subject: Fixing initialization of timing gains. Alpha should be < 1, and beta
should be << 1.
---
gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py | 13 ++++---------
gnuradio-core/src/python/gnuradio/blks2impl/dqpsk2.py | 13 ++++---------
2 files changed, 8 insertions(+), 18 deletions(-)
(limited to 'gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py')
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
index c56b598fab..4541b453b3 100644
--- a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
@@ -39,8 +39,8 @@ _def_verbose = False
_def_log = False
_def_costas_alpha = 0.1
-_def_timing_alpha = None
-_def_timing_beta = None
+_def_timing_alpha = 0.100
+_def_timing_beta = 0.010
_def_timing_max_dev = 1.5
@@ -220,7 +220,7 @@ class dbpsk2_demod(gr.hier_block2):
self._excess_bw = excess_bw
self._costas_alpha = costas_alpha
self._timing_alpha = timing_alpha
- self._timing_beta = _def_timing_alpha
+ self._timing_beta = _def_timing_beta
self._timing_max_dev=timing_max_dev
self._gray_code = gray_code
@@ -242,12 +242,7 @@ class dbpsk2_demod(gr.hier_block2):
self._costas_beta,
fmax, fmin, arity)
- # symbol clock recovery
- if not self._timing_alpha:
- self._timing_alpha = 2
- self._timing_beta = 0.020
-
- # RRC data filter
+ # symbol timing recovery with RRC data filter
nfilts = 32
ntaps = 11 * samples_per_symbol*nfilts
taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 1.0/float(self._samples_per_symbol), self._excess_bw, ntaps)
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/dqpsk2.py b/gnuradio-core/src/python/gnuradio/blks2impl/dqpsk2.py
index 05363bf04c..9704ac98c5 100644
--- a/gnuradio-core/src/python/gnuradio/blks2impl/dqpsk2.py
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/dqpsk2.py
@@ -39,8 +39,8 @@ _def_verbose = False
_def_log = False
_def_costas_alpha = 0.01
-_def_timing_alpha = None
-_def_timing_beta = None
+_def_timing_alpha = 0.100
+_def_timing_beta = 0.010
_def_timing_max_dev = 1.5
@@ -220,7 +220,7 @@ class dqpsk2_demod(gr.hier_block2):
self._excess_bw = excess_bw
self._costas_alpha = costas_alpha
self._timing_alpha = timing_alpha
- self._timing_beta = _def_timing_alpha
+ self._timing_beta = _def_timing_beta
self._timing_max_dev=timing_max_dev
self._gray_code = gray_code
@@ -242,12 +242,7 @@ class dqpsk2_demod(gr.hier_block2):
self._costas_beta,
fmax, fmin, arity)
- # symbol clock recovery
- if not self._timing_alpha:
- self._timing_alpha = 2
- self._timing_beta = 0.020
-
- # RRC data filter
+ # symbol timing recovery with RRC data filter
nfilts = 32
ntaps = 11 * samples_per_symbol*nfilts
taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 1.0/float(self._samples_per_symbol), self._excess_bw, ntaps)
--
cgit v1.2.3