diff options
Diffstat (limited to 'gsm-tvoid/src/lib/gsm_burst_cf.cc')
| -rwxr-xr-x | gsm-tvoid/src/lib/gsm_burst_cf.cc | 109 |
1 files changed, 57 insertions, 52 deletions
diff --git a/gsm-tvoid/src/lib/gsm_burst_cf.cc b/gsm-tvoid/src/lib/gsm_burst_cf.cc index a91c569..a584cd6 100755 --- a/gsm-tvoid/src/lib/gsm_burst_cf.cc +++ b/gsm-tvoid/src/lib/gsm_burst_cf.cc @@ -9,21 +9,23 @@ #include <stdio.h> #include <gri_mmse_fir_interpolator_cc.h> -gsm_burst_cf_sptr gsm_make_burst_cf (float sample_rate) +gsm_burst_cf_sptr gsm_make_burst_cf (gr_feval_ll *t,float sample_rate) { - return gsm_burst_cf_sptr (new gsm_burst_cf (sample_rate)); + return gsm_burst_cf_sptr (new gsm_burst_cf (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 -static const int MIN_OUT = 1; // minimum number of output streams +static const int MIN_OUT = 0; // minimum number of output streams static const int MAX_OUT = 1; // maximum number of output streams -gsm_burst_cf::gsm_burst_cf (float sample_rate) : +gsm_burst_cf::gsm_burst_cf (gr_feval_ll *t, float sample_rate) : + gsm_burst(t), gr_block ( "burst_cf", gr_make_io_signature (MIN_IN, MAX_IN, sizeof (gr_complex)), gr_make_io_signature (MIN_OUT, MAX_OUT, USEFUL_BITS * sizeof (float))), d_clock_counter(0.0), + d_mu(0.5), d_last_sample(0.0,0.0), d_interp(new gri_mmse_fir_interpolator_cc()) @@ -36,7 +38,7 @@ gsm_burst_cf::gsm_burst_cf (float sample_rate) : fprintf(stderr,"Sample interval : %e\n",d_sample_interval); fprintf(stderr,"Relative sample rate : %g\n",d_relative_sample_rate); - set_history(4); + set_history(4); //need history for interpolator } @@ -63,41 +65,39 @@ int gsm_burst_cf::general_work (int noutput_items, int ii=0; int rval = 0; //default to no output + int do_output = output_items.size() > 0 ? 1 : 0; int ninput = ninput_items[0]; //fprintf(stderr,"#i=%d/#o=%d",n_input,noutput_items); - int ni = ninput - d_interp->ntaps(); // interpolator need -4/+3 samples NTAPS = 8 + int ni = ninput - d_interp->ntaps() - 16; // interpolator need -4/+3 samples NTAPS = 8 , - 16 for safety margin while (( rval < noutput_items) && ( ii < ni ) ) { //clock symbols //TODO: this is very basic and can be improved. Need tracking... //TODO: use burst_start offsets as timing feedback //TODO: save complex samples for Viterbi EQ - if ( d_clock_counter >= GSM_SYMBOL_PERIOD) { - - d_clock_counter -= GSM_SYMBOL_PERIOD; //reset clock for next sample, keep the remainder - - //float mu = 1.0 - d_clock_counter / GSM_SYMBOL_PERIOD; - float mu = d_clock_counter / GSM_SYMBOL_PERIOD; - gr_complex sample = d_interp->interpolate (&in[ii], mu); //FIXME: this seems noisy, make sure it is being used correctly + + //from m&m + gr_complex sample = d_interp->interpolate (&in[ii], d_mu); //FIXME: this seems noisy, make sure it is being used correctly + + gr_complex conjprod = sample * conj(d_last_sample); + float diff_angle = gr_fast_atan2f(imag(conjprod), real(conjprod)); - gr_complex conjprod = sample * conj(d_last_sample); - float diff_angle = gr_fast_atan2f(imag(conjprod), real(conjprod)); + d_last_sample = sample; - d_last_sample = sample; - - 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_bbuf_pos++; - - if ( d_bbuf_pos >= BBUF_SIZE ) { - - if (get_burst()) { - //found a burst, send to output + 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_bbuf_pos++; + + if ( d_bbuf_pos >= BBUF_SIZE ) { + + if (get_burst()) { + //found a burst, send to output + if (do_output) { //ensure that output data is in range int b = d_burst_start; if (b < 0) @@ -106,31 +106,36 @@ int gsm_burst_cf::general_work (int noutput_items, b = 2 * MAX_CORR_DIST - 1; memcpy(out+rval*USEFUL_BITS, d_burst_buffer + b, USEFUL_BITS*sizeof(float)); - rval++; - - switch ( d_clock_options & QB_MASK ) { - case QB_QUARTER: //extra 1/4 bit each burst - d_clock_counter -= GSM_SYMBOL_PERIOD / 4.0; - break; - case QB_FULL04: //extra bit on timeslot 0 & 4 - if (!(d_ts%4)) - d_clock_counter -= GSM_SYMBOL_PERIOD; - 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); } - } - } - - d_clock_counter += d_sample_interval; - d_sample_count++; - ii++; + rval++; + + switch ( d_clock_options & QB_MASK ) { + case QB_QUARTER: //extra 1/4 bit each burst + d_mu -= d_relative_sample_rate / 4.0; + //d_clock_counter -= GSM_SYMBOL_PERIOD / 4.0; + break; + case QB_FULL04: //extra bit on timeslot 0 & 4 + if (!(d_ts%4)) + d_mu -= d_relative_sample_rate; + //d_clock_counter -= GSM_SYMBOL_PERIOD; + 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); + } + } + + //TODO: timing adjust + //d_mu = d_mu + d_omega + d_gain_mu * mm_val; + d_mu += d_relative_sample_rate; + ii += (int)floor(d_mu); + d_sample_count += (int)floor(d_mu); + d_mu -= floor(d_mu); } //fprintf(stderr,"/ii=%d/rval=%d\n",ii,rval); |