diff options
| -rw-r--r-- | gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.cc | 33 | ||||
| -rw-r--r-- | gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.h | 1 |
2 files changed, 16 insertions, 18 deletions
diff --git a/gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.cc b/gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.cc index d4b14c594..48eb849ab 100644 --- a/gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.cc +++ b/gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.cc @@ -47,6 +47,8 @@ gr_pfb_arb_resampler_ccf::gr_pfb_arb_resampler_ccf (float rate, gr_make_io_signature (1, 1, sizeof(gr_complex))), d_updated (false) { + d_acc = 0; // start accumulator at 0 + /* The number of filters is specified by the user as the filter size; this is also the interpolation rate of the filter. We use it and the rate provided to determine the decimation rate. This acts as a @@ -131,23 +133,15 @@ void gr_pfb_arb_resampler_ccf::create_diff_taps(const std::vector<float> &newtaps, std::vector<float> &difftaps) { - float maxtap = 1e-20; + // Calculate the differential taps (derivative filter) by taking the difference + // between two taps. Duplicate the last one to make both filters the same length. + float tap; difftaps.clear(); - difftaps.push_back(0); //newtaps[0]); - for(unsigned int i = 1; i < newtaps.size()-1; i++) { - float tap = newtaps[i+1] - newtaps[i-1]; + for(unsigned int i = 0; i < newtaps.size()-1; i++) { + tap = newtaps[i+1] - newtaps[i]; difftaps.push_back(tap); - if(tap > maxtap) { - maxtap = tap; - } - } - difftaps.push_back(0);//-newtaps[newtaps.size()-1]); - - // Scale the differential taps; helps scale error term to better update state - // FIXME: should this be scaled this way or use the same gain as the taps? - for(unsigned int i = 0; i < difftaps.size(); i++) { - difftaps[i] /= maxtap; } + difftaps.push_back(tap); } void @@ -188,14 +182,17 @@ gr_pfb_arb_resampler_ccf::general_work (int noutput_items, // start j by wrapping around mod the number of channels while((j < d_int_rate) && (i < noutput_items)) { - // Take the current filter output + // Take the current filter and derivative filter output o0 = d_filters[j]->filter(&in[count]); o1 = d_diff_filters[j]->filter(&in[count]); - out[i] = o0 + o1*d_flt_rate; // linearly interpolate between samples + out[i] = o0 + o1*d_acc; // linearly interpolate between samples i++; - - j += d_dec_rate; + + // Adjust accumulator and index into filterbank + d_acc += d_flt_rate; + j += d_dec_rate + (int)floor(d_acc); + d_acc = fmodf(d_acc, 1.0); } if(i < noutput_items) { // keep state for next entry float ss = (int)(j / d_int_rate); // number of items to skip ahead by diff --git a/gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.h b/gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.h index 531e9726f..b99ad286b 100644 --- a/gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.h +++ b/gnuradio-core/src/lib/filter/gr_pfb_arb_resampler_ccf.h @@ -118,6 +118,7 @@ class gr_pfb_arb_resampler_ccf : public gr_block unsigned int d_int_rate; // the number of filters (interpolation rate) unsigned int d_dec_rate; // the stride through the filters (decimation rate) float d_flt_rate; // residual rate for the linear interpolation + float d_acc; unsigned int d_last_filter; int d_start_index; unsigned int d_taps_per_filter; |