diff options
Diffstat (limited to 'gsm-tvoid/src/lib/gsm_burst_cf.cc')
| -rwxr-xr-x | gsm-tvoid/src/lib/gsm_burst_cf.cc | 58 |
1 files changed, 31 insertions, 27 deletions
diff --git a/gsm-tvoid/src/lib/gsm_burst_cf.cc b/gsm-tvoid/src/lib/gsm_burst_cf.cc index a584cd6..a7d0e11 100755 --- a/gsm-tvoid/src/lib/gsm_burst_cf.cc +++ b/gsm-tvoid/src/lib/gsm_burst_cf.cc @@ -20,24 +20,26 @@ 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 (gr_feval_ll *t, float sample_rate) : - gsm_burst(t), - gr_block ( "burst_cf", + 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))), + gr_make_io_signature (MIN_OUT, MAX_OUT, USEFUL_BITS * sizeof (float)) //TODO: pad to ^2 = 256 ? + ), + gsm_burst(t), d_clock_counter(0.0), - d_mu(0.5), d_last_sample(0.0,0.0), - d_interp(new gri_mmse_fir_interpolator_cc()) + mm(sample_rate / GSM_SYMBOL_RATE), + 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; + //d_sample_interval = 1.0 / sample_rate; + //d_omega = 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); - +// fprintf(stderr,"Sample interval : %e\n",d_sample_interval); +// fprintf(stderr,"Relative sample rate : %g\n",d_omega); + set_history(4); //need history for interpolator } @@ -51,10 +53,9 @@ void gsm_burst_cf::forecast (int noutput_items, gr_vector_int &ninput_items_requ { unsigned ninputs = ninput_items_required.size (); for (unsigned i = 0; i < ninputs; i++) - ninput_items_required[i] = noutput_items * (int)ceil(d_relative_sample_rate) * BBUF_SIZE + history(); + ninput_items_required[i] = noutput_items * (int)ceil(mm.d_omega) * BBUF_SIZE + history(); } - int gsm_burst_cf::general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, @@ -65,7 +66,8 @@ 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 num_outputs = output_items.size(); + int do_output = num_outputs > 0 ? 1 : 0; int ninput = ninput_items[0]; //fprintf(stderr,"#i=%d/#o=%d",n_input,noutput_items); @@ -75,17 +77,19 @@ int gsm_burst_cf::general_work (int noutput_items, 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 - //from m&m - gr_complex sample = d_interp->interpolate (&in[ii], d_mu); //FIXME: this seems noisy, make sure it is being used correctly + //get interpolated sample + gr_complex x_0 = d_interp->interpolate (&in[ii], mm.d_mu); - gr_complex conjprod = sample * conj(d_last_sample); + //calulate phase difference (demod) + gr_complex conjprod = x_0 * conj(d_last_sample); float diff_angle = gr_fast_atan2f(imag(conjprod), real(conjprod)); - d_last_sample = sample; - + //mM&M + //mm.update(x_0); //mm_c + mm.update(diff_angle); //mm_f + 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 @@ -111,12 +115,12 @@ int gsm_burst_cf::general_work (int noutput_items, switch ( d_clock_options & QB_MASK ) { case QB_QUARTER: //extra 1/4 bit each burst - d_mu -= d_relative_sample_rate / 4.0; + mm.d_mu -= mm.d_omega / 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; + mm.d_mu -= mm.d_omega; //d_clock_counter -= GSM_SYMBOL_PERIOD; break; case QB_NONE: //don't adjust for quarter bits at all @@ -130,12 +134,12 @@ int gsm_burst_cf::general_work (int noutput_items, } } - //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); + //process mu / ii advance + ii += (int)floor(mm.d_mu); + d_sample_count += (int)floor(mm.d_mu); + mm.d_mu -= floor(mm.d_mu); + + d_last_sample = x_0; } //fprintf(stderr,"/ii=%d/rval=%d\n",ii,rval); |