--- /dev/null
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 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_decimator_ccf.h>
+#include <gr_fir_ccf.h>
+#include <gr_fir_util.h>
+#include <gri_fft.h>
+#include <gr_io_signature.h>
+#include <gr_expj.h>
+#include <cstdio>
+
+gr_pfb_decimator_ccf_sptr gr_make_pfb_decimator_ccf (unsigned int decim,
+ const std::vector<float> &taps,
+ unsigned int channel)
+{
+ return gr_pfb_decimator_ccf_sptr (new gr_pfb_decimator_ccf (decim, taps, channel));
+}
+
+
+gr_pfb_decimator_ccf::gr_pfb_decimator_ccf (unsigned int decim,
+ const std::vector<float> &taps,
+ unsigned int channel)
+ : gr_sync_block ("pfb_decimator_ccf",
+ gr_make_io_signature (decim, decim, sizeof(gr_complex)),
+ gr_make_io_signature (1, 1, sizeof(gr_complex))),
+ d_updated (false)
+{
+ d_rate = decim;
+ d_filters = std::vector<gr_fir_ccf*>(d_rate);
+ d_chan = channel;
+ d_rotator = new gr_complex[d_rate];
+
+ // Create an FIR filter for each channel and zero out the taps
+ std::vector<float> vtaps(0, d_rate);
+ for(unsigned int i = 0; i < d_rate; i++) {
+ d_filters[i] = gr_fir_util::create_gr_fir_ccf(vtaps);
+ d_rotator[i] = gr_expj(i*2*M_PI*d_chan/d_rate);
+ }
+
+ // Now, actually set the filters' taps
+ set_taps(taps);
+
+ // Create the FFT to handle the output de-spinning of the channels
+ d_fft = new gri_fft_complex (d_rate, false);
+}
+
+gr_pfb_decimator_ccf::~gr_pfb_decimator_ccf ()
+{
+ for(unsigned int i = 0; i < d_rate; i++) {
+ delete d_filters[i];
+ }
+}
+
+void
+gr_pfb_decimator_ccf::set_taps (const std::vector<float> &taps)
+{
+ unsigned int i,j;
+
+ unsigned int ntaps = taps.size();
+ d_taps_per_filter = (unsigned int)ceil((double)ntaps/(double)d_rate);
+
+ // Create d_numchan vectors to store each channel's taps
+ d_taps.resize(d_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 = taps;
+ while((float)(tmp_taps.size()) < d_rate*d_taps_per_filter) {
+ tmp_taps.push_back(0.0);
+ }
+
+ // Partition the filter
+ for(i = 0; i < d_rate; i++) {
+ // Each channel uses all d_taps_per_filter with 0's if not enough taps to fill out
+ d_taps[i] = std::vector<float>(d_taps_per_filter, 0);
+ for(j = 0; j < d_taps_per_filter; j++) {
+ d_taps[i][j] = tmp_taps[i + j*d_rate]; // add taps to channels in reverse order
+ }
+
+ // Build a filter for each channel and add it's taps to it
+ d_filters[i]->set_taps(d_taps[i]);
+ }
+
+ // Set the history to ensure enough input items for each filter
+ set_history (d_taps_per_filter);
+
+ d_updated = true;
+}
+
+void
+gr_pfb_decimator_ccf::print_taps()
+{
+ unsigned int i, j;
+ for(i = 0; i < d_rate; i++) {
+ printf("filter[%d]: [", i);
+ for(j = 0; j < d_taps_per_filter; j++) {
+ printf(" %.4e", d_taps[i][j]);
+ }
+ printf("]\n\n");
+ }
+}
+
+#define ROTATEFFT
+
+int
+gr_pfb_decimator_ccf::work (int noutput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items)
+{
+ gr_complex *in;
+ gr_complex *out = (gr_complex *) output_items[0];
+
+ if (d_updated) {
+ d_updated = false;
+ return 0; // history requirements may have changed.
+ }
+
+ int i;
+ for(i = 0; i < noutput_items; i++) {
+ // Move through filters from bottom to top
+ out[i] = 0;
+ for(int j = d_rate-1; j >= 0; j--) {
+ // Take in the items from the first input stream to d_rate
+ in = (gr_complex*)input_items[d_rate - 1 - j];
+
+ // Filter current input stream from bottom filter to top
+ // The rotate them by expj(j*k*2pi/M) where M is the number of filters
+ // (the decimation rate) and k is the channel number to extract
+
+ // This is the real math that goes on; we abuse the FFT to do this quickly
+ // for decimation rates > N where N is a small number (~5):
+ // out[i] += d_filters[j]->filter(&in[i])*gr_expj(j*d_chan*2*M_PI/d_rate);
+#ifdef ROTATEFFT
+ d_fft->get_inbuf()[j] = d_filters[j]->filter(&in[i]);
+#else
+ out[i] += d_filters[j]->filter(&in[i])*d_rotator[i];
+#endif
+ }
+
+#ifdef ROTATEFFT
+ // Perform the FFT to do the complex multiply despinning for all channels
+ d_fft->execute();
+
+ // Select only the desired channel out
+ out[i] = d_fft->get_outbuf()[d_chan];
+#endif
+
+ }
+
+ return noutput_items;
+}
projects / debian / gnuradio / blobdiff