--- /dev/null
+/* -*- c++ -*- */
+/*
+ * Copyright 2009,2010 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gr_pfb_arb_resampler_ccf.h>
+#include <gr_fir_ccf.h>
+#include <gr_fir_util.h>
+#include <gr_io_signature.h>
+#include <cstdio>
+
+gr_pfb_arb_resampler_ccf_sptr gr_make_pfb_arb_resampler_ccf (float rate,
+ const std::vector<float> &taps,
+ unsigned int filter_size)
+{
+ return gr_pfb_arb_resampler_ccf_sptr (new gr_pfb_arb_resampler_ccf (rate, taps,
+ filter_size));
+}
+
+
+gr_pfb_arb_resampler_ccf::gr_pfb_arb_resampler_ccf (float rate,
+ const std::vector<float> &taps,
+ unsigned int filter_size)
+ : gr_block ("pfb_arb_resampler_ccf",
+ gr_make_io_signature (1, 1, sizeof(gr_complex)),
+ 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
+ rational resampler. The flt_rate is calculated as the residual
+ between the integer decimation rate and the real decimation rate and
+ will be used to determine to interpolation point of the resampling
+ process.
+ */
+ d_int_rate = filter_size;
+ d_dec_rate = (unsigned int)floor(d_int_rate/rate);
+ d_flt_rate = (d_int_rate/rate) - d_dec_rate;
+
+ // Store the last filter between calls to work
+ d_last_filter = 0;
+
+ d_start_index = 0;
+
+ d_filters = std::vector<gr_fir_ccf*>(d_int_rate);
+ d_diff_filters = std::vector<gr_fir_ccf*>(d_int_rate);
+
+ // Create an FIR filter for each channel and zero out the taps
+ std::vector<float> vtaps(0, d_int_rate);
+ for(int i = 0; i < d_int_rate; i++) {
+ d_filters[i] = gr_fir_util::create_gr_fir_ccf(vtaps);
+ d_diff_filters[i] = gr_fir_util::create_gr_fir_ccf(vtaps);
+ }
+
+ // Now, actually set the filters' taps
+ std::vector<float> dtaps;
+ create_diff_taps(taps, dtaps);
+ create_taps(taps, d_taps, d_filters);
+ create_taps(dtaps, d_dtaps, d_diff_filters);
+}
+
+gr_pfb_arb_resampler_ccf::~gr_pfb_arb_resampler_ccf ()
+{
+ for(unsigned int i = 0; i < d_int_rate; i++) {
+ delete d_filters[i];
+ }
+}
+
+void
+gr_pfb_arb_resampler_ccf::create_taps (const std::vector<float> &newtaps,
+ std::vector< std::vector<float> > &ourtaps,
+ std::vector<gr_fir_ccf*> &ourfilter)
+{
+ int i,j;
+
+ unsigned int ntaps = newtaps.size();
+ d_taps_per_filter = (unsigned int)ceil((double)ntaps/(double)d_int_rate);
+
+ // Create d_numchan vectors to store each channel's taps
+ ourtaps.resize(d_int_rate);
+
+ // Make a vector of the taps plus fill it out with 0's to fill
+ // each polyphase filter with exactly d_taps_per_filter
+ std::vector<float> tmp_taps;
+ tmp_taps = newtaps;
+ while((float)(tmp_taps.size()) < d_int_rate*d_taps_per_filter) {
+ tmp_taps.push_back(0.0);
+ }
+
+ // Partition the filter
+ for(i = 0; i < d_int_rate; i++) {
+ // Each channel uses all d_taps_per_filter with 0's if not enough taps to fill out
+ ourtaps[d_int_rate-1-i] = std::vector<float>(d_taps_per_filter, 0);
+ for(j = 0; j < d_taps_per_filter; j++) {
+ ourtaps[d_int_rate - 1 - i][j] = tmp_taps[i + j*d_int_rate];
+ }
+
+ // Build a filter for each channel and add it's taps to it
+ ourfilter[i]->set_taps(ourtaps[d_int_rate-1-i]);
+ }
+
+ // Set the history to ensure enough input items for each filter
+ set_history (d_taps_per_filter + 1);
+
+ d_updated = true;
+}
+
+void
+gr_pfb_arb_resampler_ccf::create_diff_taps(const std::vector<float> &newtaps,
+ std::vector<float> &difftaps)
+{
+ // 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();
+ for(unsigned int i = 0; i < newtaps.size()-1; i++) {
+ tap = newtaps[i+1] - newtaps[i];
+ difftaps.push_back(tap);
+ }
+ difftaps.push_back(tap);
+}
+
+void
+gr_pfb_arb_resampler_ccf::print_taps()
+{
+ unsigned int i, j;
+ for(i = 0; i < d_int_rate; i++) {
+ printf("filter[%d]: [", i);
+ for(j = 0; j < d_taps_per_filter; j++) {
+ printf(" %.4e", d_taps[i][j]);
+ }
+ printf("]\n");
+ }
+}
+
+int
+gr_pfb_arb_resampler_ccf::general_work (int noutput_items,
+ gr_vector_int &ninput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items)
+{
+ gr_complex *in = (gr_complex *) input_items[0];
+ gr_complex *out = (gr_complex *) output_items[0];
+
+ if (d_updated) {
+ d_updated = false;
+ return 0; // history requirements may have changed.
+ }
+
+ int i = 0, j, count = d_start_index;
+ gr_complex o0, o1;
+
+ // Restore the last filter position
+ j = d_last_filter;
+
+ // produce output as long as we can and there are enough input samples
+ while((i < noutput_items) && (count < ninput_items[0]-1)) {
+
+ // start j by wrapping around mod the number of channels
+ while((j < d_int_rate) && (i < noutput_items)) {
+ // 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_acc; // linearly interpolate between samples
+ i++;
+
+ // 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
+ count += ss; // we have fully consumed another input
+ j = j % d_int_rate; // roll filter around
+ }
+ }
+
+ // Store the current filter position and start of next sample
+ d_last_filter = j;
+ d_start_index = std::max(0, count - ninput_items[0]);
+
+ // consume all we've processed but no more than we can
+ consume_each(std::min(count, ninput_items[0]));
+ return i;
+}
projects / debian / gnuradio / blobdiff