[Commit-gnuradio] r7054 - gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general

[n4hy]

Author: n4hy
Date: 2007-11-28 21:07:04 -0700 (Wed, 28 Nov 2007)
New Revision: 7054

Modified:
   
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_math.h
   
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_ofdm_frame_sink.cc
   
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_ofdm_frame_sink.h
Log:
gr_math has branchless clipping back in with comments.  The ofdm_frame_sink has 
a 2nd order PLL added for offset correction

Modified: 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_math.h
===================================================================
--- 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_math.h
 2007-11-29 01:07:00 UTC (rev 7053)
+++ 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_math.h
 2007-11-29 04:07:04 UTC (rev 7054)
@@ -64,4 +64,17 @@
   return gr_fast_atan2f(z.imag(), z.real()); 
 }
 
+
+/* This bounds x by +/- clip without a branch */
+
+static inline float gr_branchless_clip(float x, float clip)
+{
+  float x1 = fabsf(x+clip);
+  float x2 = fabsf(x-clip);
+  x1 -= x2;
+  return 0.5*x1;
+}
+
+
+
 #endif /* _GR_MATH_H_ */

Modified: 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_ofdm_frame_sink.cc
===================================================================
--- 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_ofdm_frame_sink.cc
     2007-11-29 01:07:00 UTC (rev 7053)
+++ 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_ofdm_frame_sink.cc
     2007-11-29 04:07:04 UTC (rev 7054)
@@ -26,8 +26,12 @@
 
 #include <gr_ofdm_frame_sink.h>
 #include <gr_io_signature.h>
+#include <gr_expj.h>
+#include <gr_math.h>
+#include <math.h>
 #include <cstdio>
 #include <stdexcept>
+#include <iostream>
 
 #define VERBOSE 0
 
@@ -96,7 +100,12 @@
                                          unsigned char *out)
 {
   unsigned int i=0, bytes_produced=0;
+  gr_complex carrier;
 
+  carrier=gr_expj(d_phase);
+  std::cout << "carrier " << carrier << std::endl;
+
+  gr_complex accum_error = 0.0;
   while(i < d_occupied_carriers) {
     if(d_nresid > 0) {
       d_partial_byte |= d_resid;
@@ -106,8 +115,16 @@
     }
 
     while((d_byte_offset < 8) && (i < d_occupied_carriers)) {
-      //fprintf(stderr, "%f+j%f  = %d\n", in[i].real(), in[i].imag(), 
slicer(in[i])); 
-      unsigned char bits = slicer(in[i++]);
+      gr_complex sigrot = in[i]*carrier;
+      
+      //fprintf(stderr, "%f+j%f  = %d\n", sigrot.real(), sigrot.imag(), 
slicer(in[i])); 
+      //unsigned char bits = slicer(in[i++]);
+      unsigned char bits = slicer(sigrot);
+      i++;
+      gr_complex closest_sym = d_sym_position[bits];
+      
+      accum_error += sigrot * conj(closest_sym);
+
       if((8 - d_byte_offset) >= d_nbits) {
        d_partial_byte |= bits << (d_byte_offset);
        d_byte_offset += d_nbits;
@@ -130,7 +147,16 @@
       d_partial_byte = 0;
     }
   }
+  //std::cerr << "accum_error " << accum_error << std::endl;
 
+  float angle = arg(accum_error);
+  d_freq = d_freq - d_freq_gain*angle;
+  d_phase = d_phase + d_freq - d_phase_gain*angle;
+  if (d_phase >= 2*M_PI) d_phase -= 2*M_PI;
+  if (d_phase <0) d_phase += 2*M_PI;
+  
+  
+  std::cerr << angle << "\t" << d_freq << "\t" << d_phase << std::endl;
   return bytes_produced;
 }
 
@@ -153,7 +179,7 @@
                   gr_make_io_signature (0, 0, 0)),
     d_target_queue(target_queue), d_occupied_carriers(occupied_carriers), 
     d_byte_offset(0), d_partial_byte(0),
-    d_resid(0), d_nresid(0)
+    d_resid(0), 
d_nresid(0),d_phase(0),d_freq(0),d_phase_gain(0.25),d_freq_gain(0.25*.25*.25)
 {
   d_bytes_out = new unsigned char[d_occupied_carriers];
 
@@ -197,7 +223,12 @@
   
   if (VERBOSE)
     fprintf(stderr,">>> Entering state machine\n");
-  
+
+  if(d_state != STATE_HAVE_HEADER) {
+    d_freq = 0.0;
+    d_phase = 0.0;
+  }
+
   bytes = demapper(&in[0], d_bytes_out);
   
   switch(d_state) {

Modified: 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_ofdm_frame_sink.h
===================================================================
--- 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_ofdm_frame_sink.h
      2007-11-29 01:07:00 UTC (rev 7053)
+++ 
gnuradio/branches/developers/trondeau/ofdm2/gnuradio-core/src/lib/general/gr_ofdm_frame_sink.h
      2007-11-29 04:07:04 UTC (rev 7054)
@@ -77,6 +77,10 @@
 
   unsigned char d_resid;
   unsigned int d_nresid;
+  float d_phase;
+  float d_freq;
+  float d_freq_gain;
+  float d_phase_gain;
 
  protected:
   gr_ofdm_frame_sink(const std::vector<gr_complex> &sym_position,