diff options
| author | Tom <trondeau@vt.edu> | 2010-01-31 17:03:36 -0500 |
|---|---|---|
| committer | Tom <trondeau@vt.edu> | 2010-01-31 17:03:36 -0500 |
| commit | fd6fd94644330a29ae0598c3ff1e75ddc196e806 (patch) | |
| tree | 9b96282f5ad91310c6a261bac22483e1d22d6853 /gnuradio-core | |
| parent | cf4e5e40a77a0579f97e4306d2d51860b3b3a3f0 (diff) | |
Got this wrong before. Derivative filter taps are now calculated correctly which makes the rest of the code work. My previous test cases must have masked the problem.
Diffstat (limited to 'gnuradio-core')
| -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 d4b14c5945..48eb849ab1 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 531e9726f3..b99ad286b8 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; |