add Gardner block

git-svn-id: http://op25.osmocom.org/svn/trunk@212 65a5c917-d112-43f1-993d-58c26a4786be

repeater/src/lib/Makefile.am

@@ -66,6 +66,7 @@ _repeater_la_SOURCES = 	repeater\
 	repeater_pipe.cc		\
 	repeater_ctcss_squelch_ff.cc	\
 	repeater_squelch_base_ff.cc	\
+	repeater_gardner_symbol_recovery_cc.cc	\
 	bch.cc
 
 # magic flags
@@ -86,6 +87,7 @@ grinclude_HEADERS =			\
 	repeater_p25_frame_fb.h		\
 	repeater_imbe_decode_fb.h	\
 	repeater_pipe.h			\
+	repeater_gardner_symbol_recovery_cc.h	\
 	repeater_ctcss_squelch_ff.h
 
 

repeater/src/lib/repeater.i

@@ -13,6 +13,7 @@
 #include "repeater_imbe_decode_fb.h"
 #include "repeater_pipe.h"
 #include "repeater_ctcss_squelch_ff.h"
+#include "repeater_gardner_symbol_recovery_cc.h"
 #include <stdexcept>
 %}
 
@@ -113,3 +114,15 @@ public:
   int len() const { return d_len; }
 
 };
+
+// ----------------------------------------------------------------
+
+GR_SWIG_BLOCK_MAGIC(repeater,gardner_symbol_recovery_cc);
+
+repeater_gardner_symbol_recovery_cc_sptr repeater_make_gardner_symbol_recovery_cc (int samples_per_symbol, float timing_error_gain);
+
+class repeater_gardner_symbol_recovery_cc : public gr_sync_block
+{
+ private:
+  repeater_gardner_symbol_recovery_cc (int samples_per_symbol, float timing_error_gain);
+};

repeater/src/lib/repeater_gardner_symbol_recovery_cc.cc

@@ -0,0 +1,152 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2005,2006 Free Software Foundation, Inc.
+ *
+ * Gardner symbol recovery block for GR - Copyright 2010, KA1RBI
+ *
+ * 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_math.h>
+#include <gr_expj.h>
+#include <repeater_gardner_symbol_recovery_cc.h>
+#include <gri_mmse_fir_interpolator_cc.h>
+#include <stdexcept>
+#include <cstdio>
+#include <string.h>
+
+#define M_TWOPI (2*M_PI)
+
+// Public constructor
+
+repeater_gardner_symbol_recovery_cc_sptr 
+repeater_make_gardner_symbol_recovery_cc(int samples_per_symbol, float timing_error_gain)
+{
+  return repeater_gardner_symbol_recovery_cc_sptr (new repeater_gardner_symbol_recovery_cc (samples_per_symbol, timing_error_gain));
+}
+
+repeater_gardner_symbol_recovery_cc::repeater_gardner_symbol_recovery_cc (int samples_per_symbol, float timing_error_gain)
+  : gr_block ("repeater_gardner_symbol_recovery_cc",
+	      gr_make_io_signature (1, 1, sizeof (gr_complex)),
+	      gr_make_io_signature (1, 2, sizeof (gr_complex))),
+	      d_last_sample(0), d_interp(new gri_mmse_fir_interpolator_cc()),
+    d_verbose(gr_prefs::singleton()->get_bool("repeater_gardner_symbol_recovery_cc", "verbose", false)),
+    d_dl_index(0),
+    d_samples_per_symbol(samples_per_symbol), d_timing_error_gain(timing_error_gain), 
+    d_timing_error(0)
+{
+  assert (d_samples_per_symbol >= 2);
+  assert ((d_samples_per_symbol & 1) == 0);   // sps must be even
+
+  d_half_sps = d_samples_per_symbol >> 1;
+  d_twice_sps = d_samples_per_symbol * 2;
+  set_relative_rate (1.0 / d_samples_per_symbol);
+  set_history(d_twice_sps);			// ensure extra input is available
+  d_dl = new gr_complex[d_twice_sps*2];
+}
+
+repeater_gardner_symbol_recovery_cc::~repeater_gardner_symbol_recovery_cc ()
+{
+  delete d_interp;
+  delete d_dl;
+}
+
+void
+repeater_gardner_symbol_recovery_cc::forecast(int noutput_items, gr_vector_int &ninput_items_required)
+{
+  unsigned ninputs = ninput_items_required.size();
+  for (unsigned i=0; i < ninputs; i++)
+    ninput_items_required[i] =
+      (int) ceil((noutput_items * d_samples_per_symbol) + d_interp->ntaps());
+}
+
+// sample processing - includes slip by +/- 1 sample if error is excessive
+bool
+repeater_gardner_symbol_recovery_cc::input_sample0(gr_complex samp, gr_complex& outp) {
+	bool rc0=false, rc1=false;
+
+	if (d_timing_error >= 0.5) {
+		d_timing_error = -0.5;
+		return false;   // skip this samp
+	}
+	if (d_timing_error <= -0.5) {
+		d_timing_error =  0.5;
+		rc0 = input_sample(samp, outp);   // repeat this samp
+	}
+
+	rc1 = input_sample(samp, outp);
+	return rc0 | rc1;
+}
+
+// returns true if an output sample was generated and stored in outp
+bool
+repeater_gardner_symbol_recovery_cc::input_sample(gr_complex samp, gr_complex& outp) {
+	bool rc = false;
+
+	d_dl[d_dl_index] = samp;
+	d_dl[d_dl_index + d_twice_sps] = samp;
+	d_dl_index ++;
+	d_dl_index = d_dl_index % d_twice_sps;
+
+	if ((d_dl_index % d_samples_per_symbol) == 0) {
+		float mu = 0.5 + d_timing_error;
+		if (mu < 0.0) mu = 0.0;
+		if (mu > 1.0) mu = 1.0;
+		gr_complex interp_samp_mid = d_interp->interpolate(&d_dl[ d_dl_index ], mu);
+		gr_complex interp_samp = d_interp->interpolate(&d_dl[ d_dl_index + d_half_sps], mu);
+		outp = interp_samp;
+		float error_real = (d_last_sample.real() - interp_samp.real()) * interp_samp_mid.real();
+		float error_imag = (d_last_sample.imag() - interp_samp.imag()) * interp_samp_mid.imag();
+		d_last_sample = interp_samp;
+		float symbol_error = error_real + error_imag;
+		if (symbol_error < -1.0) symbol_error = -1.0;
+		if (symbol_error >  1.0) symbol_error =  1.0;
+		d_timing_error = d_timing_error + d_timing_error_gain * symbol_error;
+		// printf("%f\t%f\t%f\n", symbol_error, d_timing_error, mu);
+		rc = true;
+	}
+	return rc;
+}
+
+int
+repeater_gardner_symbol_recovery_cc::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];
+  gr_complex *out = (gr_complex *) output_items[0];
+
+  int i=0, o=0;
+
+  while((o < noutput_items) && (i < ninput_items[0])) {
+     gr_complex interp_sample;
+     if(input_sample0(in[i++], interp_sample)) {
+      out[o++] = interp_sample;
+     }
+  }
+
+  consume_each(i);
+  return o;
+}

repeater/src/lib/repeater_gardner_symbol_recovery_cc.h

@@ -0,0 +1,88 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004 Free Software Foundation, Inc.
+ *
+ * Gardner symbol recovery block for GR - Copyright 2010, KA1RBI
+ *
+ * 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_REPEATER_GARDNER_SYMBOL_RECOVERY_CC_H
+#define	INCLUDED_REPEATER_GARDNER_SYMBOL_RECOVERY_CC_H
+
+#include <gr_block.h>
+#include <gr_complex.h>
+#include <gr_math.h>
+
+class gri_mmse_fir_interpolator_cc;
+
+class repeater_gardner_symbol_recovery_cc;
+typedef boost::shared_ptr<repeater_gardner_symbol_recovery_cc> repeater_gardner_symbol_recovery_cc_sptr;
+
+// public constructor
+repeater_gardner_symbol_recovery_cc_sptr 
+repeater_make_gardner_symbol_recovery_cc (int samples_per_symbol, float timing_error_gain);
+
+/*!
+ * \brief Gardner based repeater gardner_symbol_recovery block with complex input, complex output.
+ * \ingroup sync_blk
+ *
+ * This implements a Gardner discrete-time error-tracking synchronizer.
+ *
+ * input samples should be within normalized range of -1.0 thru +1.0
+ *
+ * includes some simplifying approximations KA1RBI
+ */
+class repeater_gardner_symbol_recovery_cc : public gr_block
+{
+ public:
+  ~repeater_gardner_symbol_recovery_cc ();
+  void forecast(int noutput_items, gr_vector_int &ninput_items_required);
+  int general_work (int noutput_items,
+		    gr_vector_int &ninput_items,
+		    gr_vector_const_void_star &input_items,
+		    gr_vector_void_star &output_items);
+  void set_verbose (bool verbose) { d_verbose = verbose; }
+
+protected:
+  bool input_sample0(gr_complex, gr_complex& outp);
+  bool input_sample(gr_complex, gr_complex& outp);
+  repeater_gardner_symbol_recovery_cc (int samples_per_symbol, float timing_error_gain);
+
+ private:
+
+  gr_complex                    d_last_sample;
+  gri_mmse_fir_interpolator_cc 	*d_interp;
+  bool			        d_verbose;
+
+  gr_complex			*d_dl;
+  int				d_dl_index;
+
+  int				d_samples_per_symbol;
+  float				d_timing_error_gain;
+  int				d_half_sps;
+  int				d_twice_sps;
+
+  float				d_timing_error;
+
+  friend repeater_gardner_symbol_recovery_cc_sptr
+  repeater_make_gardner_symbol_recovery_cc (int samples_per_symbol, float timing_error_gain);
+
+};
+
+#endif