From fb9671bfc0f3d1e2fe81099e72ff0c09f07d9171 Mon Sep 17 00:00:00 2001
From: leo <leo@brix.(none)>
Date: Thu, 24 Apr 2008 02:25:11 +0100
Subject: initial

---
 gsm-tvoid/src/lib/gsm_burst_sink_c.cc | 141 ++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 gsm-tvoid/src/lib/gsm_burst_sink_c.cc

(limited to 'gsm-tvoid/src/lib/gsm_burst_sink_c.cc')

diff --git a/gsm-tvoid/src/lib/gsm_burst_sink_c.cc b/gsm-tvoid/src/lib/gsm_burst_sink_c.cc
new file mode 100644
index 0000000..58787bb
--- /dev/null
+++ b/gsm-tvoid/src/lib/gsm_burst_sink_c.cc
@@ -0,0 +1,141 @@
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "gsm_burst_sink_c.h"
+#include <gr_io_signature.h>
+#include <gr_math.h>
+#include <stdio.h>
+#include <gri_mmse_fir_interpolator_cc.h>
+
+gsm_burst_sink_c_sptr gsm_make_burst_sink_c (gr_feval_ll *t,float sample_rate)
+{
+  return gsm_burst_sink_c_sptr (new gsm_burst_sink_c(t,sample_rate));
+}
+
+static const int MIN_IN = 1;	// minimum number of input streams
+static const int MAX_IN = 1;	// maximum number of input streams
+
+gsm_burst_sink_c::gsm_burst_sink_c (gr_feval_ll *t, float sample_rate) : 
+	gsm_burst(t),
+	gr_sync_block (	"burst_sink_c",
+				gr_make_io_signature (MIN_IN, MAX_IN, sizeof (gr_complex)),
+				gr_make_io_signature (0,0,0)
+			),
+	d_clock_counter(0.0),
+	d_mu(0.5),
+	d_last_sample(0.0,0.0),
+	d_ii(0),
+	d_interp(new gri_mmse_fir_interpolator_cc())
+
+{
+
+	//clocking parameters
+	d_sample_interval = 1.0 / sample_rate;
+	d_relative_sample_rate = sample_rate / GSM_SYMBOL_RATE;
+	
+	fprintf(stderr,"Sample interval      : %e\n",d_sample_interval);
+	fprintf(stderr,"Relative sample rate : %g\n",d_relative_sample_rate);
+	
+	//we need history for interpolator taps and some saftey relative to relative rate
+	int hist = d_interp->ntaps(); // + 16;  // interpolator need -4/+3 samples NTAPS = 8  , 16 for safety margin
+	set_history(hist); //need history for interpolator
+	
+}
+
+gsm_burst_sink_c::~gsm_burst_sink_c ()
+{
+	delete d_interp;
+}
+
+void gsm_burst_sink_c::shift_burst(int shift_bits)
+{
+	//fprintf(stderr,"sft:%d\n",shift_bits);
+
+	assert(shift_bits >= 0);
+	assert(shift_bits < BBUF_SIZE );
+
+	gr_complex *p_src = d_complex_burst + shift_bits;
+	gr_complex *p_dst = d_complex_burst;
+	int num = BBUF_SIZE - shift_bits;
+	
+	memmove(p_dst,p_src,num * sizeof(gr_complex));  //need memmove because of overlap
+
+	//DON'T adjust the buffer positions, the superclass method will do that...
+	//d_bbuf_pos -= shift_bits;
+	//call the parent method to shift the float version
+	gsm_burst::shift_burst(shift_bits);
+}
+
+//TODO: put everything but GR stuff in a common complex type class (share w/ gsm_burst_cf)
+int gsm_burst_sink_c::work(int noutput_items,
+		gr_vector_const_void_star &input_items,
+		gr_vector_void_star &output_items)
+
+{
+	const gr_complex *in = (const gr_complex *) input_items[0];
+	
+//	fprintf(stderr,"#o=%d",noutput_items);
+
+	assert( d_ii >= 0 );
+
+	while ( d_ii < noutput_items ) {
+		//clock symbols 
+
+		gr_complex sample = d_interp->interpolate (&in[d_ii], d_mu);
+		
+		gr_complex conjprod = sample * conj(d_last_sample);
+		float diff_angle = gr_fast_atan2f(imag(conjprod), real(conjprod));
+
+		d_last_sample = sample;
+
+#if 1		
+		assert(d_bbuf_pos <= BBUF_SIZE );
+		
+		if (d_bbuf_pos >= 0) {	//could be negative offset from burst alignment.  TODO: perhaps better just to add some padding to the buffer
+			d_burst_buffer[d_bbuf_pos] = diff_angle;
+			d_complex_burst[d_bbuf_pos] = sample;
+		}
+		
+		d_bbuf_pos++;
+		
+		if ( d_bbuf_pos >= BBUF_SIZE ) { 
+			if (get_burst()) {
+				//adjust timing
+				//TODO: generate timing error from burst buffer (phase & freq)
+							
+				switch ( d_clock_options & QB_MASK ) {
+				case QB_QUARTER: //extra 1/4 bit each burst
+					d_mu -= d_relative_sample_rate / 4.0;
+					break;
+				case QB_FULL04:	//extra bit on timeslot 0 & 4
+					if (!(d_ts%4))
+						d_mu -= d_relative_sample_rate;
+					break;
+				case QB_NONE:	//don't adjust for quarter bits at all
+				default:
+					break;
+				}
+				
+				d_last_burst_s_count = d_sample_count;
+				
+				//fprintf(stderr,"clock: %f, pos: %d\n",d_clock_counter,d_bbuf_pos);
+			}
+		}	   
+#endif			
+
+		d_mu += d_relative_sample_rate;
+		d_ii += (int)floor(d_mu);
+		//d_sample_count += (int)floor(d_mu);		//TODO: outside loop?
+		d_mu -= floor(d_mu);
+	}
+
+	//reset d_ii, accounting for advance
+	d_ii -= noutput_items;
+	
+//	fprintf(stderr,"/mu=%f",d_mu);
+//	fprintf(stderr,"/ii=%d\n",d_ii);
+
+	return noutput_items;
+}
-- 
cgit v1.2.3