merged trondeau/digital-wip2 r4193:4730 into trunk - improves digital receiver and fixes ticket:72

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@4731 221aa14e-8319-0410-a670-987f0aec2ac5

8 files changed, 815 insertions, 46 deletions

diff --git a/gnuradio-core/src/lib/general/Makefile.am b/gnuradio-core/src/lib/general/Makefile.am
index d29259b4a..3856a319a 100644
--- a/gnuradio-core/src/lib/general/Makefile.am
+++ b/gnuradio-core/src/lib/general/Makefile.am
@@ -88,6 +88,7 @@ libgeneral_la_SOURCES = 		\
 	gr_map_bb.cc			\
 	gr_math.cc			\
 	gr_misc.cc			\
+	gr_mpsk_receiver_cc.cc		\
 	gr_nlog10_ff.cc			\
 	gr_nop.cc			\
 	gr_null_sink.cc			\
@@ -211,6 +212,7 @@ grinclude_HEADERS = 			\
 	gr_map_bb.h			\
 	gr_math.h			\
 	gr_misc.h			\
+	gr_mpsk_receiver_cc.h		\
 	gr_nco.h			\
 	gr_nlog10_ff.h			\
 	gr_nop.h			\
@@ -337,6 +339,7 @@ swiginclude_HEADERS =			\
 	gr_lms_dfe_cc.i			\
 	gr_lms_dfe_ff.i			\
 	gr_map_bb.i			\
+	gr_mpsk_receiver_cc.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 b659beb52..87368f81e 100644
--- a/gnuradio-core/src/lib/general/general.i
+++ b/gnuradio-core/src/lib/general/general.i
@@ -67,6 +67,7 @@
 #include <gr_nlog10_ff.h>
 #include <gr_fake_channel_coder_pp.h>
 #include <gr_throttle.h>
+#include <gr_mpsk_receiver_cc.h>
 #include <gr_stream_to_streams.h>
 #include <gr_streams_to_stream.h>
 #include <gr_streams_to_vector.h>
@@ -157,6 +158,7 @@
 %include "gr_nlog10_ff.i"
 %include "gr_fake_channel_coder_pp.i"
 %include "gr_throttle.i"
+%include "gr_mpsk_receiver_cc.i"
 %include "gr_stream_to_streams.i"
 %include "gr_streams_to_stream.i"
 %include "gr_streams_to_vector.i"
diff --git a/gnuradio-core/src/lib/general/gr_clock_recovery_mm_cc.cc b/gnuradio-core/src/lib/general/gr_clock_recovery_mm_cc.cc
index 88cd14077..6166e25e6 100644
--- a/gnuradio-core/src/lib/general/gr_clock_recovery_mm_cc.cc
+++ b/gnuradio-core/src/lib/general/gr_clock_recovery_mm_cc.cc
@@ -133,47 +133,90 @@ gr_clock_recovery_mm_cc::general_work (int noutput_items,
   float mm_val=0;
   gr_complex u, x, y;
 
-  while(oo < noutput_items && ii < ni) {
-    d_p_2T = d_p_1T;
-    d_p_1T = d_p_0T;
-    d_p_0T = d_interp->interpolate (&in[ii], d_mu);
-
-    d_c_2T = d_c_1T;
-    d_c_1T = d_c_0T;
-    d_c_0T = slicer_0deg(d_p_0T);
-
-    x = (d_c_0T - d_c_2T) * conj(d_p_1T);
-    y = (d_p_0T - d_p_2T) * conj(d_c_1T);
-    u = y - x;
-    mm_val = u.real();
-    out[oo++] = d_p_0T;
-
-    // limit mm_val
-    if (mm_val > 1.0)
-      mm_val = 1.0;
-    else if (mm_val < -1.0)
-      mm_val = -1.0;
-
-    d_omega = d_omega + d_gain_omega * mm_val;
-    if (d_omega > d_max_omega)
-      d_omega = d_max_omega;
-    else if (d_omega < d_min_omega)
-      d_omega = d_min_omega;
-
-    d_mu = d_mu + d_omega + d_gain_mu * mm_val;
-    ii += (int)floor(d_mu);
-    d_mu -= floor(d_mu);
-
-    if(d_verbose) {
+  // This loop writes the error to the second output, if it exists
+  if (write_foptr) {
+    while(oo < noutput_items && ii < ni) {
+      d_p_2T = d_p_1T;
+      d_p_1T = d_p_0T;
+      d_p_0T = d_interp->interpolate (&in[ii], d_mu);
+
+      d_c_2T = d_c_1T;
+      d_c_1T = d_c_0T;
+      d_c_0T = slicer_0deg(d_p_0T);
+      
+      x = (d_c_0T - d_c_2T) * conj(d_p_1T);
+      y = (d_p_0T - d_p_2T) * conj(d_c_1T);
+      u = y - x;
+      mm_val = u.real();
+      out[oo++] = d_p_0T;
+      
+      // limit mm_val
+      if (mm_val > 1.0)
+	mm_val = 1.0;
+      else if (mm_val < -1.0)
+	mm_val = -1.0;
+      
+      d_omega = d_omega + d_gain_omega * mm_val;
+      if (d_omega > d_max_omega)
+	d_omega = d_max_omega;
+      else if (d_omega < d_min_omega)
+	d_omega = d_min_omega;
+      
+      d_mu = d_mu + d_omega + d_gain_mu * mm_val;
+      ii += (int)floor(d_mu);
+      d_mu -= floor(d_mu);
+      
+      #if 0
       printf("%f\t%f\n", d_omega, d_mu);
-    }
-
-    // write the error signal to the second output
-    if (write_foptr)
+      #endif
+      
+      // write the error signal to the second output
       foptr[oo-1] = gr_complex(d_mu,0);
-
-    if (ii < 0)	// clamp it.  This should only happen with bogus input
-      ii = 0;
+      
+      if (ii < 0)	// clamp it.  This should only happen with bogus input
+	ii = 0;
+    }
+  }
+  // This loop does not write to the second output (ugly, but faster)
+  else {
+    while(oo < noutput_items && ii < ni) {
+      d_p_2T = d_p_1T;
+      d_p_1T = d_p_0T;
+      d_p_0T = d_interp->interpolate (&in[ii], d_mu);
+
+      d_c_2T = d_c_1T;
+      d_c_1T = d_c_0T;
+      d_c_0T = slicer_0deg(d_p_0T);
+      
+      x = (d_c_0T - d_c_2T) * conj(d_p_1T);
+      y = (d_p_0T - d_p_2T) * conj(d_c_1T);
+      u = y - x;
+      mm_val = u.real();
+      out[oo++] = d_p_0T;
+      
+      // limit mm_val
+      if (mm_val > 1.0)
+	mm_val = 1.0;
+      else if (mm_val < -1.0)
+	mm_val = -1.0;
+      
+      d_omega = d_omega + d_gain_omega * mm_val;
+      if (d_omega > d_max_omega)
+	d_omega = d_max_omega;
+      else if (d_omega < d_min_omega)
+	d_omega = d_min_omega;
+      
+      d_mu = d_mu + d_omega + d_gain_mu * mm_val;
+      ii += (int)floor(d_mu);
+      d_mu -= floor(d_mu);
+      
+      if(d_verbose) {
+	printf("%f\t%f\n", d_omega, d_mu);
+      }
+            
+      if (ii < 0)	// clamp it.  This should only happen with bogus input
+	ii = 0;
+    }
   }
 
   if (ii > 0){
diff --git a/gnuradio-core/src/lib/general/gr_clock_recovery_mm_cc.h b/gnuradio-core/src/lib/general/gr_clock_recovery_mm_cc.h
index 0a2d73a94..c9a50358c 100644
--- a/gnuradio-core/src/lib/general/gr_clock_recovery_mm_cc.h
+++ b/gnuradio-core/src/lib/general/gr_clock_recovery_mm_cc.h
@@ -41,10 +41,11 @@ gr_make_clock_recovery_mm_cc (float omega, float gain_omega, float mu, float gai
  * \ingroup block
  *
  * This implements the Mueller and Müller (M&M) discrete-time error-tracking synchronizer.
- *
- * See "Digital Communication Receivers: Synchronization, Channel
- * Estimation and Signal Processing" by Heinrich Meyr, Marc Moeneclaey, & Stefan Fechtel.
- * ISBN 0-471-50275-8.
+ * The complex version here is based on:
+ * Modified Mueller and Muller clock recovery circuit
+ * Based:
+ *    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.
  */
 class gr_clock_recovery_mm_cc : public gr_block
 {
diff --git a/gnuradio-core/src/lib/general/gr_correlate_access_code_bb.cc b/gnuradio-core/src/lib/general/gr_correlate_access_code_bb.cc
index 18253e968..078ff5028 100644
--- a/gnuradio-core/src/lib/general/gr_correlate_access_code_bb.cc
+++ b/gnuradio-core/src/lib/general/gr_correlate_access_code_bb.cc
@@ -88,7 +88,7 @@ gr_correlate_access_code_bb::work (int noutput_items,
 {
   const unsigned char *in = (const unsigned char *) input_items[0];
   unsigned char *out = (unsigned char *) output_items[0];
-  
+
   for (int i = 0; i < noutput_items; i++){
 
     // compute output value
@@ -109,9 +109,12 @@ gr_correlate_access_code_bb::work (int noutput_items,
     // test for access code with up to threshold errors
     new_flag = (nwrong <= d_threshold);
 
-#if 0   
+#if VERBOSE
     if(new_flag) {
-      printf("%llx  ==>  %llx  :  d_flip=%u\n", d_access_code, d_data_reg, d_flip);
+      fprintf(stderr, "access code found: %llx\n", d_access_code);
+    }
+    else {
+      fprintf(stderr, "%llx  ==>  %llx\n", d_access_code, d_data_reg);
     }
 #endif
 
diff --git a/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.cc b/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.cc
new file mode 100644
index 000000000..87b2f541a
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.cc
@@ -0,0 +1,345 @@
+/* -*- c++ -*- */
+/*
+ * 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 2, 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_mpsk_receiver_cc.h>
+#include <stdexcept>
+#include <gr_math.h>
+#include <gr_expj.h>
+#include <gri_mmse_fir_interpolator_cc.h>
+
+
+#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_mpsk_receiver_cc_sptr 
+gr_make_mpsk_receiver_cc(unsigned int M, float theta,
+			 float alpha, float beta,
+			 float fmin, float fmax,
+			 float mu, float gain_mu, 
+			 float omega, float gain_omega, float omega_rel)
+{
+  return gr_mpsk_receiver_cc_sptr (new gr_mpsk_receiver_cc (M, theta, 
+							    alpha, beta,
+							    fmin, fmax,
+							    mu, gain_mu, 
+							    omega, gain_omega, omega_rel));
+}
+
+gr_mpsk_receiver_cc::gr_mpsk_receiver_cc (unsigned int M, float theta, 
+					  float alpha, float beta,
+					  float fmin, float fmax,
+					  float mu, float gain_mu, 
+					  float omega, float gain_omega, float omega_rel)
+  : gr_block ("mpsk_receiver_cc",
+	      gr_make_io_signature (1, 1, sizeof (gr_complex)),
+	      gr_make_io_signature (1, 1, sizeof (gr_complex))),
+    d_M(M), d_theta(theta), 
+    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),
+    d_mu(mu), d_gain_mu(gain_mu), d_gain_omega(gain_omega), 
+    d_omega_rel(omega_rel), d_max_omega(0), d_min_omega(0),
+    d_p_2T(0), d_p_1T(0), d_p_0T(0), d_c_2T(0), d_c_1T(0), d_c_0T(0)
+{
+  d_interp = new gri_mmse_fir_interpolator_cc();
+  d_dl_idx = 0;
+
+  set_omega(omega);
+
+  if (omega <= 0.0)
+    throw std::out_of_range ("clock rate must be > 0");
+  if (gain_mu <  0  || gain_omega < 0)
+    throw std::out_of_range ("Gains must be non-negative");
+  
+  assert(d_interp->ntaps() <= DLLEN);
+  
+  // zero double length delay line.
+  for (unsigned int i = 0; i < 2 * DLLEN; i++)
+    d_dl[i] = gr_complex(0.0,0.0);
+
+  // build the constellation vector from M
+  make_constellation();
+  
+  // Select a phase detector and a decision maker for the modulation order
+  switch(d_M) {
+  case 2:  // optimized algorithms for BPSK
+    d_phase_error_detector = &gr_mpsk_receiver_cc::phase_error_detector_generic; //bpsk;
+    d_decision = &gr_mpsk_receiver_cc::decision_generic; //bpsk;
+    break;
+
+  case 4: // optimized algorithms for QPSK
+    d_phase_error_detector = &gr_mpsk_receiver_cc::phase_error_detector_generic; //qpsk;
+    d_decision = &gr_mpsk_receiver_cc::decision_generic; //qpsk;
+    break;
+
+  default: // generic algorithms for any M (power of 2?) but not pretty
+    d_phase_error_detector = &gr_mpsk_receiver_cc::phase_error_detector_generic;
+    d_decision = &gr_mpsk_receiver_cc::decision_generic;
+    break;
+  }
+
+  set_history(3);			// ensure 2 extra input sample is available
+}
+
+gr_mpsk_receiver_cc::~gr_mpsk_receiver_cc ()
+{
+  delete d_interp;
+}
+
+void
+gr_mpsk_receiver_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_omega) + d_interp->ntaps());
+  //ninput_items_required[i] = (int)(d_omega);
+
+}
+
+// FIXME add these back in an test difference in performance
+float
+gr_mpsk_receiver_cc::phase_error_detector_qpsk(gr_complex sample) const
+{
+  float phase_error = ((sample.real()>0 ? 1.0 : -1.0) * sample.imag() -
+		       (sample.imag()>0 ? 1.0 : -1.0) * sample.real());
+  return -phase_error;
+}
+
+// FIXME add these back in an test difference in performance
+float
+gr_mpsk_receiver_cc::phase_error_detector_bpsk(gr_complex sample) const
+{
+  return (sample.real()*sample.imag());
+}
+
+float gr_mpsk_receiver_cc::phase_error_detector_generic(gr_complex sample) const
+{
+  //return gr_fast_atan2f(sample*conj(d_constellation[d_current_const_point]));
+  return -arg(sample*conj(d_constellation[d_current_const_point]));
+}
+
+// FIXME add these back in an test difference in performance
+unsigned int
+gr_mpsk_receiver_cc::decision_bpsk(gr_complex sample) const
+{
+  unsigned int index = 0;
+
+  // Implements a 1-demensional slicer
+  if(sample.real() > 0)
+    index = 1;
+  return index;
+}
+
+// FIXME add these back in an test difference in performance
+unsigned int
+gr_mpsk_receiver_cc::decision_qpsk(gr_complex sample) const
+{
+  unsigned int index = 0;
+
+  // Implements a simple slicer function
+  if((sample.real() < 0) && (sample.imag() > 0))
+    index = 1;
+  else if((sample.real() < 0) && (sample.imag() < 0))
+    index = 2;
+  else
+    index = 3;
+  return index;
+}
+
+unsigned int
+gr_mpsk_receiver_cc::decision_generic(gr_complex sample) const
+{
+  unsigned int min_m = 0;
+  float min_s = 65535;
+  
+  // Develop all possible constellation points and find the one that minimizes
+  // the Euclidean distance (error) with the sample
+  for(unsigned int m=0; m < d_M; m++) {
+    gr_complex diff = norm(d_constellation[m] - sample);
+    
+    if(fabs(diff.real()) < min_s) {
+      min_s = fabs(diff.real());
+      min_m = m;
+    }
+  }
+  // Return the index of the constellation point that minimizes the error
+  return min_m;
+}
+
+
+void
+gr_mpsk_receiver_cc::make_constellation()
+{
+  for(unsigned int m=0; m < d_M; m++) {
+    d_constellation.push_back(gr_expj((M_TWOPI/d_M)*m));
+  }
+}
+
+void
+gr_mpsk_receiver_cc::mm_sampler(const gr_complex symbol)
+{
+  gr_complex sample, nco;
+
+  d_mu--;             // skip a number of symbols between sampling
+  d_phase += d_freq;  // increment the phase based on the frequency of the rotation
+
+  // Keep phase clamped and not walk to infinity
+  while(d_phase>M_TWOPI)
+    d_phase -= M_TWOPI;
+  while(d_phase<-M_TWOPI)
+    d_phase += M_TWOPI;
+
+  nco = gr_expj(d_phase+d_theta);   // get the NCO value for derotating the current sample
+  sample = nco*symbol;      // get the downconverted symbol
+  
+  // Fill up the delay line for the interpolator
+  d_dl[d_dl_idx] = sample;
+  d_dl[(d_dl_idx + DLLEN)] = sample;  // put this in the second half of the buffer for overflows
+  d_dl_idx = (d_dl_idx+1) % DLLEN;    // Keep the delay line index in bounds
+}
+
+void
+gr_mpsk_receiver_cc::mm_error_tracking(gr_complex sample)
+{
+  gr_complex u, x, y;
+  float mm_error = 0;
+
+  // Make sample timing corrections
+
+  // set the delayed samples
+  d_p_2T = d_p_1T;
+  d_p_1T = d_p_0T;
+  d_p_0T = sample;
+  d_c_2T = d_c_1T;
+  d_c_1T = d_c_0T;
+  
+  d_current_const_point = (*this.*d_decision)(d_p_0T);  // make a decision on the sample value
+  d_c_0T = d_constellation[d_current_const_point];
+  
+  x = (d_c_0T - d_c_2T) * conj(d_p_1T);
+  y = (d_p_0T - d_p_2T) * conj(d_c_1T);
+  u = y - x;
+  mm_error = u.real();   // the error signal is in the real part
+  
+  // limit mm_val
+  if (mm_error > 1.0)
+    mm_error = 1.0;
+  else if (mm_error < -1.0)
+    mm_error = -1.0;
+  
+  d_omega = d_omega + d_gain_omega * mm_error;  // update omega based on loop error
+
+  // make sure we don't walk away
+  if (d_omega > d_max_omega)
+    d_omega = d_max_omega;
+  else if (d_omega < d_min_omega)
+    d_omega = d_min_omega;
+  
+  d_mu += d_omega + d_gain_mu * mm_error;   // update mu based on loop error
+  
+#if VERBOSE_MM
+  printf("mm: mu: %f   omega: %f  mm_error: %f  sample: %f+j%f  constellation: %f+j%f\n", 
+	 d_mu, d_omega, mm_error, sample.real(), sample.imag(), 
+	 d_constellation[d_current_const_point].real(), d_constellation[d_current_const_point].imag());
+#endif
+}
+
+
+void
+gr_mpsk_receiver_cc::phase_error_tracking(gr_complex sample)
+{
+  float phase_error = 0;
+
+  // Make phase and frequency corrections based on sampled value
+  phase_error = (*this.*d_phase_error_detector)(sample);
+
+  if (phase_error > 1)
+    phase_error = 1;
+  else if (phase_error < -1)
+    phase_error = -1;  
+
+  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
+  if (d_freq > d_max_freq)
+    d_freq = d_max_freq;
+  else if (d_freq < d_min_freq)
+    d_freq = d_min_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[d_current_const_point].real(), d_constellation[d_current_const_point].imag());
+#endif
+}
+
+int
+gr_mpsk_receiver_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(i < ninput_items[0]) {    
+  while(o < noutput_items) {
+    while((d_mu > 1) && (i < ninput_items[0]))  {
+      mm_sampler(in[i]);   // puts symbols into a buffer and adjusts d_mu
+      i++;
+    }
+    
+    if(i < ninput_items[0]) {
+      gr_complex interp_sample = d_interp->interpolate(&d_dl[d_dl_idx], d_mu);
+       
+      mm_error_tracking(interp_sample);     // corrects M&M sample time
+      phase_error_tracking(interp_sample);  // corrects phase and frequency offsets
+
+      out[o++] = interp_sample;
+    }
+  }
+
+  #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;
+}
diff --git a/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.h b/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.h
new file mode 100644
index 000000000..f096af484
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.h
@@ -0,0 +1,313 @@
+/* -*- 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 2, 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_MPSK_RECEIVER_CC_H
+#define	INCLUDED_GR_MPSK_RECEIVER_CC_H
+
+#include <gr_block.h>
+#include <gr_complex.h>
+#include <fstream>
+
+class gri_mmse_fir_interpolator_cc;
+
+class gr_mpsk_receiver_cc;
+typedef boost::shared_ptr<gr_mpsk_receiver_cc> gr_mpsk_receiver_cc_sptr;
+
+// public constructor
+gr_mpsk_receiver_cc_sptr 
+gr_make_mpsk_receiver_cc (unsigned int M, float theta, 
+			  float alpha, float beta,
+			  float fmin, float fmax,
+			  float mu, float gain_mu, 
+			  float omega, float gain_omega, float omega_rel);
+
+/*!
+ * \brief This block takes care of receiving M-PSK modulated signals through phase, frequency, and symbol
+ * synchronization. 
+ * \ingroup block
+ *
+ * This block takes care of receiving M-PSK modulated signals through phase, frequency, and symbol
+ * synchronization. It performs carrier frequency and phase locking as well as symbol timing recovery. 
+ * It works with (D)BPSK, (D)QPSK, and (D)8PSK as tested currently. It should also work for OQPSK and 
+ * PI/4 DQPSK.
+ *
+ * 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. There are optimized phase error detectors for BPSK and QPSK, but 8PSK
+ * is done using a brute-force computation of the constellation points to find the minimum.
+ *
+ * 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_mpsk_receiver_cc : public gr_block
+{
+ public:
+  ~gr_mpsk_receiver_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);
+
+
+  // Member functions related to the symbol tracking portion of the receiver
+  //! (M&M) Returns current value of mu
+  float mu() const { return d_mu;}
+
+  //! (M&M) Returns current value of omega
+  float omega() const { return d_omega;}
+
+  //! (M&M) Returns mu gain factor
+  float gain_mu() const { return d_gain_mu;}
+
+  //! (M&M) Returns omega gain factor
+  float gain_omega() const { return d_gain_omega;}
+
+  //! (M&M) Sets value of mu
+  void set_mu (float mu) { d_mu = mu; }
+  
+  //! (M&M) Sets value of omega and its min and max values 
+  void set_omega (float omega) { 
+    d_omega = omega;
+    d_min_omega = omega*(1.0 - d_omega_rel);
+    d_max_omega = omega*(1.0 + d_omega_rel);
+  }
+
+  //! (M&M) Sets value for mu gain factor
+  void set_gain_mu (float gain_mu) { d_gain_mu = gain_mu; }
+
+  //! (M&M) Sets value for omega gain factor
+  void set_gain_omega (float gain_omega) { d_gain_omega = gain_omega; }
+
+
+
+  // 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 M	        modulation order of the M-PSK modulation
+   * \param theta	any constant phase rotation from the real axis of the constellation
+   * \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
+   * \param mu          initial parameter for the interpolator [0,1]
+   * \param gain_mu     gain parameter of the M&M error signal to adjust mu (~0.05)
+   * \param omega       initial value for the number of symbols between samples (~number of samples/symbol)
+   * \param gain_omega  gain parameter to adjust omega based on the error (~omega^2/4)
+   * \param omega_rel   sets the maximum (omega*(1+omega_rel)) and minimum (omega*(1+omega_rel)) omega (~0.005)
+   *
+   * The constructor also chooses which phase detector and decision maker to use in the work loop based on the
+   * value of M.
+   */
+  gr_mpsk_receiver_cc (unsigned int M, float theta, 
+		       float alpha, float beta,
+		       float fmin, float fmax,
+		       float mu, float gain_mu, 
+		       float omega, float gain_omega, float omega_rel);
+
+  void make_constellation();
+  void mm_sampler(const gr_complex symbol);
+  void mm_error_tracking(gr_complex sample);
+  void phase_error_tracking(gr_complex sample);
+
+
+/*!
+   * \brief Phase error detector for MPSK modulations.
+   *
+   * \param sample   the I&Q sample from which to determine the phase error
+   *
+   * This function determines the phase error for any MPSK signal by creating a set of PSK constellation points
+   * and doing a brute-force search to see which point minimizes the Euclidean distance. This point is then used
+   * to derotate the sample to the real-axis and a atan (using the fast approximation function) to determine the
+   * phase difference between the incoming sample and the real constellation point
+   *
+   * This should be cleaned up and made more efficient.
+   *
+   * \returns the approximated phase error.
+ */
+  float phase_error_detector_generic(gr_complex sample) const; // generic for M but more costly
+
+ /*!
+   * \brief Phase error detector for BPSK modulation.
+   *
+   * \param sample   the I&Q sample from which to determine the phase error
+   *
+   * This function determines the phase error using a simple BPSK phase error detector by multiplying the real
+   * and imaginary (the error signal) components together. As the imaginary part goes to 0, so does this error.
+   *
+   * \returns the approximated phase error.
+ */
+  float phase_error_detector_bpsk(gr_complex sample) const;    // optimized for BPSK
+
+ /*!
+   * \brief Phase error detector for QPSK modulation.
+   *
+   * \param sample   the I&Q sample from which to determine the phase error
+   *
+   * This function determines the phase error using the limiter approach in a standard 4th order Costas loop
+   *
+   * \returns the approximated phase error.
+ */
+  float phase_error_detector_qpsk(gr_complex sample) const;
+
+
+
+ /*!
+   * \brief Decision maker for a generic MPSK constellation.
+   *
+   * \param sample   the baseband I&Q sample from which to make the decision
+   *
+   * This decision maker is a generic implementation that does a brute-force search 
+   * for the constellation point that minimizes the error between it and the incoming signal.
+   *
+   * \returns the index to d_constellation that minimizes the error/
+ */
+  unsigned int decision_generic(gr_complex sample) const;
+
+
+ /*!
+   * \brief Decision maker for BPSK constellation.
+   *
+   * \param sample   the baseband I&Q sample from which to make the decision
+   *
+   * This decision maker is a simple slicer function that makes a decision on the symbol based on its
+   * placement on the real axis of greater than 0 or less than 0; the quadrature component is always 0.
+   *
+   * \returns the index to d_constellation that minimizes the error/
+ */
+  unsigned int decision_bpsk(gr_complex sample) const;
+  
+
+ /*!
+   * \brief Decision maker for QPSK constellation.
+   *
+   * \param sample   the baseband I&Q sample from which to make the decision
+   *
+   * This decision maker is a simple slicer function that makes a decision on the symbol based on its
+   * placement versus both axes and returns which quadrant the symbol is in.
+   *
+   * \returns the index to d_constellation that minimizes the error/
+ */
+  unsigned int decision_qpsk(gr_complex sample) const;
+
+  private:
+  unsigned int d_M;
+  float        d_theta;
+
+  // 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;
+
+/*!
+   * \brief Decision maker function pointer 
+   *
+   * \param sample   the baseband I&Q sample from which to make the decision
+   *
+   * This is a function pointer that is set in the constructor to point to the proper decision function
+   * for the specified constellation order.
+   *
+   * \return index into d_constellation point that is the closest to the recieved sample
+ */
+  unsigned int (gr_mpsk_receiver_cc::*d_decision)(gr_complex sample) const; // pointer to decision function
+
+
+  std::vector<gr_complex> d_constellation;
+  unsigned int d_current_const_point;
+
+  // Members related to symbol timing
+  float d_mu, d_gain_mu;
+  float d_omega, d_gain_omega, d_omega_rel, d_max_omega, d_min_omega;
+  gr_complex d_p_2T, d_p_1T, d_p_0T;
+  gr_complex d_c_2T, d_c_1T, d_c_0T;
+
+ /*!
+   * \brief Phase error detector function pointer 
+   *
+   * \param sample   the I&Q sample from which to determine the phase error
+   *
+   * This is a function pointer that is set in the constructor to point to the proper phase error detector
+   * function for the specified constellation order.
+ */
+  float (gr_mpsk_receiver_cc::*d_phase_error_detector)(gr_complex sample) const;
+
+
+  //! get interpolated value
+  gri_mmse_fir_interpolator_cc 	*d_interp;
+  
+  //! delay line length.
+  static const unsigned int DLLEN = 8;
+  
+  //! delay line plus some length for overflow protection
+  gr_complex d_dl[2*DLLEN];
+  
+  //! index to delay line
+  unsigned int d_dl_idx;
+
+  friend gr_mpsk_receiver_cc_sptr
+  gr_make_mpsk_receiver_cc (unsigned int M, float theta,
+			    float alpha, float beta,
+			    float fmin, float fmax,
+			    float mu, float gain_mu, 
+			    float omega, float gain_omega, float omega_rel);
+};
+
+#endif
diff --git a/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.i b/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.i
new file mode 100644
index 000000000..661b4d04d
--- /dev/null
+++ b/gnuradio-core/src/lib/general/gr_mpsk_receiver_cc.i
@@ -0,0 +1,59 @@
+/* -*- 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 2, 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,mpsk_receiver_cc);
+
+gr_mpsk_receiver_cc_sptr gr_make_mpsk_receiver_cc (unsigned int M, float theta,
+						   float alpha, float beta,
+						   float fmin, float fmax,
+						   float mu, float gain_mu, 
+						   float omega, float gain_omega, float omega_rel);
+class gr_mpsk_receiver_cc : public gr_block
+{
+ private:
+  gr_mpsk_receiver_cc (unsigned int M,float theta,
+				float alpha, float beta,
+				float fmin, float fmax,
+				float mu, float gain_mu, 
+				float omega, float gain_omega, float omega_rel);
+public:
+  float mu() const { return d_mu;}
+  float omega() const { return d_omega;}
+  float gain_mu() const { return d_gain_mu;}
+  float gain_omega() const { return d_gain_omega;}
+  void set_mu (float mu) { d_mu = mu; }
+  void set_omega (float omega) { 
+    d_omega = omega;
+    d_min_omega = omega*(1.0 - d_omega_rel);
+    d_max_omega = omega*(1.0 + d_omega_rel);
+  }
+  void set_gain_mu (float gain_mu) { d_gain_mu = gain_mu; }
+  void set_gain_omega (float gain_omega) { d_gain_omega = gain_omega; }
+  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; } 
+};