3 * Copyright 2010 Free Software Foundation, Inc.
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27 #include <gri_fft_filter_ccc_generic.h>
35 gri_fft_filter_ccc_generic::gri_fft_filter_ccc_generic (int decimation,
36 const std::vector<gr_complex> &taps)
37 : d_fftsize(-1), d_decimation(decimation), d_fwdfft(0), d_invfft(0)
42 gri_fft_filter_ccc_generic::~gri_fft_filter_ccc_generic ()
50 print_vector_complex(const std::string label, const std::vector<gr_complex> &x)
53 for (unsigned i = 0; i < x.size(); i++)
54 std::cout << x[i] << " ";
61 * determines d_ntaps, d_nsamples, d_fftsize, d_xformed_taps
64 gri_fft_filter_ccc_generic::set_taps (const std::vector<gr_complex> &taps)
67 compute_sizes(taps.size());
69 d_tail.resize(tailsize());
70 for (i = 0; i < tailsize(); i++)
73 gr_complex *in = d_fwdfft->get_inbuf();
74 gr_complex *out = d_fwdfft->get_outbuf();
76 float scale = 1.0 / d_fftsize;
78 // Compute forward xform of taps.
79 // Copy taps into first ntaps slots, then pad with zeros
80 for (i = 0; i < d_ntaps; i++)
81 in[i] = taps[i] * scale;
83 for (; i < d_fftsize; i++)
86 d_fwdfft->execute(); // do the xform
88 // now copy output to d_xformed_taps
89 for (i = 0; i < d_fftsize; i++)
90 d_xformed_taps[i] = out[i];
95 // determine and set d_ntaps, d_nsamples, d_fftsize
98 gri_fft_filter_ccc_generic::compute_sizes(int ntaps)
100 int old_fftsize = d_fftsize;
102 d_fftsize = (int) (2 * pow(2.0, ceil(log(ntaps) / log(2))));
103 d_nsamples = d_fftsize - d_ntaps + 1;
106 fprintf(stderr, "gri_fft_filter_ccc_generic: ntaps = %d, fftsize = %d, nsamples = %d\n",
107 d_ntaps, d_fftsize, d_nsamples);
109 assert(d_fftsize == d_ntaps + d_nsamples -1 );
111 if (d_fftsize != old_fftsize){ // compute new plans
114 d_fwdfft = new gri_fft_complex(d_fftsize, true);
115 d_invfft = new gri_fft_complex(d_fftsize, false);
116 d_xformed_taps.resize(d_fftsize);
121 gri_fft_filter_ccc_generic::filter (int nitems, const gr_complex *input, gr_complex *output)
125 int ninput_items = nitems * d_decimation;
127 for (int i = 0; i < ninput_items; i += d_nsamples){
129 memcpy(d_fwdfft->get_inbuf(), &input[i], d_nsamples * sizeof(gr_complex));
131 for (j = d_nsamples; j < d_fftsize; j++)
132 d_fwdfft->get_inbuf()[j] = 0;
134 d_fwdfft->execute(); // compute fwd xform
136 gr_complex *a = d_fwdfft->get_outbuf();
137 gr_complex *b = &d_xformed_taps[0];
138 gr_complex *c = d_invfft->get_inbuf();
140 for (j = 0; j < d_fftsize; j+=1) { // filter in the freq domain
144 d_invfft->execute(); // compute inv xform
146 // add in the overlapping tail
148 for (j = 0; j < tailsize(); j++)
149 d_invfft->get_outbuf()[j] += d_tail[j];
151 // copy nsamples to output
153 while (j < d_nsamples) {
154 *output++ = d_invfft->get_outbuf()[j];
157 dec_ctr = (j - d_nsamples);
160 memcpy(&d_tail[0], d_invfft->get_outbuf() + d_nsamples,
161 tailsize() * sizeof(gr_complex));
164 assert(dec_ctr == 0);