3 * Copyright 2009,2010 Free Software Foundation, Inc.
5 * This file is part of GNU Radio
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27 #include <gr_pfb_channelizer_ccf.h>
28 #include <gr_fir_ccf.h>
29 #include <gr_fir_util.h>
31 #include <gr_io_signature.h>
35 gr_pfb_channelizer_ccf_sptr gr_make_pfb_channelizer_ccf (unsigned int numchans,
36 const std::vector<float> &taps,
37 float oversample_rate)
39 return gr_pfb_channelizer_ccf_sptr (new gr_pfb_channelizer_ccf (numchans, taps,
44 gr_pfb_channelizer_ccf::gr_pfb_channelizer_ccf (unsigned int numchans,
45 const std::vector<float> &taps,
46 float oversample_rate)
47 : gr_sync_interpolator ("pfb_channelizer_ccf",
48 gr_make_io_signature (numchans, numchans, sizeof(gr_complex)),
49 gr_make_io_signature (1, 1, numchans*sizeof(gr_complex)),
51 d_updated (false), d_oversample_rate(oversample_rate)
53 d_numchans = numchans;
54 d_filters = std::vector<gr_fir_ccf*>(d_numchans);
56 // Create an FIR filter for each channel and zero out the taps
57 std::vector<float> vtaps(0, d_numchans);
58 for(unsigned int i = 0; i < d_numchans; i++) {
59 d_filters[i] = gr_fir_util::create_gr_fir_ccf(vtaps);
62 // Now, actually set the filters' taps
65 // Create the FFT to handle the output de-spinning of the channels
66 d_fft = new gri_fft_complex (d_numchans, false);
69 gr_pfb_channelizer_ccf::~gr_pfb_channelizer_ccf ()
71 for(unsigned int i = 0; i < d_numchans; i++) {
77 gr_pfb_channelizer_ccf::set_taps (const std::vector<float> &taps)
81 unsigned int ntaps = taps.size();
82 d_taps_per_filter = (unsigned int)ceil((double)ntaps/(double)d_numchans);
84 // Create d_numchan vectors to store each channel's taps
85 d_taps.resize(d_numchans);
87 // Make a vector of the taps plus fill it out with 0's to fill
88 // each polyphase filter with exactly d_taps_per_filter
89 std::vector<float> tmp_taps;
91 while((float)(tmp_taps.size()) < d_numchans*d_taps_per_filter) {
92 tmp_taps.push_back(0.0);
95 // Partition the filter
96 for(i = 0; i < d_numchans; i++) {
97 // Each channel uses all d_taps_per_filter with 0's if not enough taps to fill out
98 d_taps[i] = std::vector<float>(d_taps_per_filter, 0);
99 for(j = 0; j < d_taps_per_filter; j++) {
100 d_taps[i][j] = tmp_taps[i + j*d_numchans]; // add taps to channels in reverse order
103 // Build a filter for each channel and add it's taps to it
104 d_filters[i]->set_taps(d_taps[i]);
107 // Set the history to ensure enough input items for each filter
108 set_history (d_taps_per_filter);
114 gr_pfb_channelizer_ccf::print_taps()
117 for(i = 0; i < d_numchans; i++) {
118 printf("filter[%d]: [", i);
119 for(j = 0; j < d_taps_per_filter; j++) {
120 printf(" %.4e", d_taps[i][j]);
128 gr_pfb_channelizer_ccf::work (int noutput_items,
129 gr_vector_const_void_star &input_items,
130 gr_vector_void_star &output_items)
132 gr_complex *in = (gr_complex *) input_items[0];
133 gr_complex *out = (gr_complex *) output_items[0];
137 return 0; // history requirements may have changed.
142 int N = d_oversample_rate;
143 int lastidx = 0, i = 1, k = 0, m = 0, n = 0;
145 int *idx = new int[M];
146 for(k = 0; k < M; k++)
149 while(i <= noutput_items/N) {
152 for(n = N-1; n >= 0; n--) {
153 for(k = 0; k < M/N; k++)
154 idx[(lastidx + k) % M]++;
155 lastidx = (lastidx + M/N) % M;
159 for(m = 0; m < M; m++) {
160 in = (gr_complex*)input_items[m];
165 d_fft->get_inbuf()[y] = d_filters[x]->filter(&in[idx[m]]);
169 memcpy(out, d_fft->get_outbuf(), d_numchans*sizeof(gr_complex));
177 int M = d_oversample_rate;
181 int n=1, i=-1, j=0, last;
184 // Although the filters change, we use this look up table
185 // to set the index of the FFT input buffer, which equivalently
186 // performs the FFT shift operation on every other turn.
187 int *idxlut = new int[N];
188 for(int ii = 0; ii < N; ii++) {
189 idxlut[ii] = N - ((ii + r) % N) - 1;
192 while(n <= noutput_items/M) {
197 in = (gr_complex*)input_items[j];
198 //d_fft->get_inbuf()[(i + state*r) % N] = d_filters[i]->filter(&in[n]);
199 d_fft->get_inbuf()[idxlut[j]] = d_filters[i]->filter(&in[n]);
206 in = (gr_complex*)input_items[j];
207 //d_fft->get_inbuf()[(i + state*r) % N] = d_filters[i]->filter(&in[n-1]);
208 d_fft->get_inbuf()[idxlut[j]] = d_filters[i]->filter(&in[n-1]);
216 // despin through FFT
218 memcpy(out, d_fft->get_outbuf(), d_numchans*sizeof(gr_complex));
226 return noutput_items;