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[Commit-gnuradio] [gnuradio] 02/04: digital: adding use of tanh and snr
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[Commit-gnuradio] [gnuradio] 02/04: digital: adding use of tanh and snr info to costas loop. |
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Date: |
Tue, 21 Oct 2014 21:04:45 +0000 (UTC) |
This is an automated email from the git hooks/post-receive script.
trondeau pushed a commit to branch master
in repository gnuradio.
commit fdf13bdc0640f4ffa892c9bebedf74274bc6ea82
Author: Tom Rondeau <address@hidden>
Date: Tue Oct 21 16:07:53 2014 -0400
digital: adding use of tanh and snr info to costas loop.
---
gr-digital/grc/digital_costas_loop_cc.xml | 84 ++++++++++++++--------
.../include/gnuradio/digital/costas_loop_cc.h | 9 ++-
gr-digital/lib/costas_loop_cc_impl.cc | 68 ++++++++++++++++--
gr-digital/lib/costas_loop_cc_impl.h | 45 ++++++++++--
gr-digital/python/digital/qa_costas_loop_cc.py | 22 +++---
5 files changed, 174 insertions(+), 54 deletions(-)
diff --git a/gr-digital/grc/digital_costas_loop_cc.xml
b/gr-digital/grc/digital_costas_loop_cc.xml
index 668c43d..40db3a4 100644
--- a/gr-digital/grc/digital_costas_loop_cc.xml
+++ b/gr-digital/grc/digital_costas_loop_cc.xml
@@ -5,34 +5,60 @@
###################################################
-->
<block>
- <name>Costas Loop</name>
- <key>digital_costas_loop_cc</key>
- <import>from gnuradio import digital</import>
- <make>digital.costas_loop_cc($w, $order)</make>
- <callback>set_loop_bandwidth($w)</callback>
- <param>
- <name>Loop Bandwidth</name>
- <key>w</key>
- <type>real</type>
- </param>
- <param>
- <name>Order</name>
- <key>order</key>
- <type>int</type>
- </param>
- <sink>
- <name>in</name>
- <type>complex</type>
- </sink>
- <source>
- <name>out</name>
- <type>complex</type>
- </source>
+ <name>Costas Loop</name>
+ <key>digital_costas_loop_cc</key>
+ <import>from gnuradio import digital</import>
+ <make>digital.costas_loop_cc($w, $order, $use_snr)</make>
+ <callback>set_loop_bandwidth($w)</callback>
- <!-- Optional Outputs -->
- <source>
- <name>frequency</name>
- <type>float</type>
- <optional>1</optional>
- </source>
+ <param>
+ <name>Loop Bandwidth</name>
+ <key>w</key>
+ <type>real</type>
+ </param>
+
+ <param>
+ <name>Order</name>
+ <key>order</key>
+ <type>int</type>
+ </param>
+
+ <param>
+ <name>Use SNR</name>
+ <key>use_snr</key>
+ <value>False</value>
+ <type>enum</type>
+ <hide>part</hide>
+ <option>
+ <name>Yes</name>
+ <key>True</key>
+ </option>
+ <option>
+ <name>No</name>
+ <key>False</key>
+ </option>
+ </param>
+
+ <sink>
+ <name>in</name>
+ <type>complex</type>
+ </sink>
+
+ <sink>
+ <name>noise</name>
+ <type>message</type>
+ <optional>1</optional>
+ </sink>
+
+ <source>
+ <name>out</name>
+ <type>complex</type>
+ </source>
+
+ <!-- Optional Outputs -->
+ <source>
+ <name>frequency</name>
+ <type>float</type>
+ <optional>1</optional>
+ </source>
</block>
diff --git a/gr-digital/include/gnuradio/digital/costas_loop_cc.h
b/gr-digital/include/gnuradio/digital/costas_loop_cc.h
index d924d96..ff5b9b9 100644
--- a/gr-digital/include/gnuradio/digital/costas_loop_cc.h
+++ b/gr-digital/include/gnuradio/digital/costas_loop_cc.h
@@ -1,6 +1,6 @@
/* -*- c++ -*- */
/*
- * Copyright 2006,2011,2012 Free Software Foundation, Inc.
+ * Copyright 2006,2011,2012,2014 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
@@ -58,6 +58,9 @@ namespace gr {
* The Costas loop can have two output streams:
* \li stream 1 (required) is the baseband I and Q;
* \li stream 2 (optional) is the normalized frequency of the loop
+ *
+ * There is a single optional message input:
+ * \li noise: A noise floor estimate used to calculate the SNR of a sample.
*/
class DIGITAL_API costas_loop_cc
: virtual public sync_block,
@@ -72,8 +75,10 @@ namespace gr {
*
* \param loop_bw internal 2nd order loop bandwidth (~ 2pi/100)
* \param order the loop order, either 2, 4, or 8
+ * \param use_snr Use or ignore SNR estimates (from noise message port)
+ * in measurements; also uses tanh instead of slicing.
*/
- static sptr make(float loop_bw, int order);
+ static sptr make(float loop_bw, int order, bool use_snr=false);
/*!
* Returns the current value of the loop error.
diff --git a/gr-digital/lib/costas_loop_cc_impl.cc
b/gr-digital/lib/costas_loop_cc_impl.cc
index 36f95ac..a53045a 100644
--- a/gr-digital/lib/costas_loop_cc_impl.cc
+++ b/gr-digital/lib/costas_loop_cc_impl.cc
@@ -35,37 +35,52 @@ namespace gr {
namespace digital {
costas_loop_cc::sptr
- costas_loop_cc::make(float loop_bw, int order)
+ costas_loop_cc::make(float loop_bw, int order, bool use_snr)
{
return gnuradio::get_initial_sptr
- (new costas_loop_cc_impl(loop_bw, order));
+ (new costas_loop_cc_impl(loop_bw, order, use_snr));
}
- costas_loop_cc_impl::costas_loop_cc_impl(float loop_bw, int order)
+ costas_loop_cc_impl::costas_loop_cc_impl(float loop_bw, int order, bool
use_snr)
: sync_block("costas_loop_cc",
io_signature::make(1, 1, sizeof(gr_complex)),
io_signature::make2(1, 2, sizeof(gr_complex),
sizeof(float))),
blocks::control_loop(loop_bw, 1.0, -1.0),
- d_order(order), d_error(0), d_phase_detector(NULL)
+ d_order(order), d_error(0), d_noise(1.0), d_phase_detector(NULL)
{
// Set up the phase detector to use based on the constellation order
switch(d_order) {
case 2:
- d_phase_detector = &costas_loop_cc_impl::phase_detector_2;
+ if(use_snr)
+ d_phase_detector = &costas_loop_cc_impl::phase_detector_snr_2;
+ else
+ d_phase_detector = &costas_loop_cc_impl::phase_detector_2;
break;
case 4:
- d_phase_detector = &costas_loop_cc_impl::phase_detector_4;
+ if(use_snr)
+ d_phase_detector = &costas_loop_cc_impl::phase_detector_snr_4;
+ else
+ d_phase_detector = &costas_loop_cc_impl::phase_detector_4;
break;
case 8:
- d_phase_detector = &costas_loop_cc_impl::phase_detector_8;
+ if(use_snr)
+ d_phase_detector = &costas_loop_cc_impl::phase_detector_snr_8;
+ else
+ d_phase_detector = &costas_loop_cc_impl::phase_detector_8;
break;
default:
throw std::invalid_argument("order must be 2, 4, or 8");
break;
}
+
+ message_port_register_in(pmt::mp("noise"));
+ set_msg_handler(
+ pmt::mp("noise"),
+ boost::bind(&costas_loop_cc_impl::handle_set_noise,
+ this, _1));
}
costas_loop_cc_impl::~costas_loop_cc_impl()
@@ -114,11 +129,50 @@ namespace gr {
}
float
+ costas_loop_cc_impl::phase_detector_snr_8(gr_complex sample) const
+ {
+ float K = (sqrt(2.0) - 1);
+ float snr = abs(sample)*abs(sample) / d_noise;
+ if(fabsf(sample.real()) >= fabsf(sample.imag())) {
+ return ((blocks::tanhf_lut(snr*sample.real()) * sample.imag()) -
+ (blocks::tanhf_lut(snr*sample.imag()) * sample.real() * K));
+ }
+ else {
+ return ((blocks::tanhf_lut(snr*sample.real()) * sample.imag() * K) -
+ (blocks::tanhf_lut(snr*sample.imag()) * sample.real()));
+ }
+ }
+
+ float
+ costas_loop_cc_impl::phase_detector_snr_4(gr_complex sample) const
+ {
+ float snr = abs(sample)*abs(sample) / d_noise;
+ return ((blocks::tanhf_lut(snr*sample.real()) * sample.imag()) -
+ (blocks::tanhf_lut(snr*sample.imag()) * sample.real()));
+ }
+
+ float
+ costas_loop_cc_impl::phase_detector_snr_2(gr_complex sample) const
+ {
+ float snr = abs(sample)*abs(sample) / d_noise;
+ return blocks::tanhf_lut(snr*sample.real()) * sample.imag();
+ }
+
+ float
costas_loop_cc_impl::error() const
{
return d_error;
}
+ void
+ costas_loop_cc_impl::handle_set_noise(pmt::pmt_t msg)
+ {
+ if(pmt::is_real(msg)) {
+ d_noise = pmt::to_double(msg);
+ d_noise = powf(10.0f, d_noise/10.0f);
+ }
+ }
+
int
costas_loop_cc_impl::work(int noutput_items,
gr_vector_const_void_star &input_items,
diff --git a/gr-digital/lib/costas_loop_cc_impl.h
b/gr-digital/lib/costas_loop_cc_impl.h
index 6657242..ebd05e2 100644
--- a/gr-digital/lib/costas_loop_cc_impl.h
+++ b/gr-digital/lib/costas_loop_cc_impl.h
@@ -1,6 +1,6 @@
/* -*- c++ -*- */
/*
- * Copyright 2006,2011,2012 Free Software Foundation, Inc.
+ * Copyright 2006,2011,2012,2014 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
@@ -34,33 +34,68 @@ namespace gr {
private:
int d_order;
float d_error;
+ float d_noise;
- /*! \brief the phase detector circuit for 8th-order PSK loops
+ /*! \brief the phase detector circuit for 8th-order PSK loops.
+ *
* \param sample complex sample
* \return the phase error
*/
float phase_detector_8(gr_complex sample) const; // for 8PSK
- /*! \brief the phase detector circuit for fourth-order loops
+ /*! \brief the phase detector circuit for fourth-order loops.
+ *
* \param sample complex sample
* \return the phase error
*/
float phase_detector_4(gr_complex sample) const; // for QPSK
- /*! \brief the phase detector circuit for second-order loops
+ /*! \brief the phase detector circuit for second-order loops.
+ *
* \param sample a complex sample
* \return the phase error
*/
float phase_detector_2(gr_complex sample) const; // for BPSK
+
+ /*! \brief the phase detector circuit for 8th-order PSK
+ * loops. Uses tanh instead of slicing and the noise estimate
+ * from the message port to estimated SNR of the samples.
+ *
+ * \param sample complex sample
+ * \return the phase error
+ */
+ float phase_detector_snr_8(gr_complex sample) const; // for 8PSK
+
+ /*! \brief the phase detector circuit for fourth-order
+ * loops. Uses tanh instead of slicing and the noise estimate
+ * from the message port to estimated SNR of the samples.
+ *
+ * \param sample complex sample
+ * \return the phase error
+ */
+ float phase_detector_snr_4(gr_complex sample) const; // for QPSK
+
+ /*! \brief the phase detector circuit for second-order
+ * loops. Uses tanh instead of slicing and the noise estimate
+ * from the message port to estimated SNR of the samples.
+ *
+ * \param sample a complex sample
+ * \return the phase error
+ */
+ float phase_detector_snr_2(gr_complex sample) const; // for BPSK
+
+
float (costas_loop_cc_impl::*d_phase_detector)(gr_complex sample) const;
public:
- costas_loop_cc_impl(float loop_bw, int order);
+ costas_loop_cc_impl(float loop_bw, int order, bool use_snr=false);
~costas_loop_cc_impl();
float error() const;
+ void handle_set_noise(pmt::pmt_t msg);
+
void setup_rpc();
int work(int noutput_items,
diff --git a/gr-digital/python/digital/qa_costas_loop_cc.py
b/gr-digital/python/digital/qa_costas_loop_cc.py
index 9ecb017..e48f45c 100755
--- a/gr-digital/python/digital/qa_costas_loop_cc.py
+++ b/gr-digital/python/digital/qa_costas_loop_cc.py
@@ -1,24 +1,24 @@
#!/usr/bin/env python
#
# Copyright 2011,2013 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.
-#
+#
import random
import cmath
@@ -46,7 +46,7 @@ class test_costas_loop_cc(gr_unittest.TestCase):
self.tb.connect(self.src, self.test, self.snk)
self.tb.run()
-
+
expected_result = data
dst_data = self.snk.data()
self.assertComplexTuplesAlmostEqual(expected_result, dst_data, 5)
@@ -77,7 +77,7 @@ class test_costas_loop_cc(gr_unittest.TestCase):
rot = cmath.exp(0.2j) # some small rotation
data = [complex(2*random.randint(0,1)-1, 0) for i in xrange(100)]
-
+
N = 40 # settling time
expected_result = data[N:]
data = [rot*d for d in data]
@@ -89,7 +89,7 @@ class test_costas_loop_cc(gr_unittest.TestCase):
self.tb.run()
dst_data = self.snk.data()[N:]
-
+
# generously compare results; the loop will converge near to, but
# not exactly on, the target data
self.assertComplexTuplesAlmostEqual(expected_result, dst_data, 2)
@@ -103,7 +103,7 @@ class test_costas_loop_cc(gr_unittest.TestCase):
rot = cmath.exp(0.2j) # some small rotation
data = [complex(2*random.randint(0,1)-1, 2*random.randint(0,1)-1)
for i in xrange(100)]
-
+
N = 40 # settling time
expected_result = data[N:]
data = [rot*d for d in data]
@@ -130,7 +130,7 @@ class test_costas_loop_cc(gr_unittest.TestCase):
const = psk.psk_constellation(order)
data = [random.randint(0,7) for i in xrange(100)]
data = [2*rot*const.points()[d] for d in data]
-
+
N = 40 # settling time
expected_result = data[N:]
@@ -144,7 +144,7 @@ class test_costas_loop_cc(gr_unittest.TestCase):
self.tb.run()
dst_data = self.snk.data()[N:]
-
+
# generously compare results; the loop will converge near to, but
# not exactly on, the target data
self.assertComplexTuplesAlmostEqual(expected_result, dst_data, 2)