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27 #include <gri_fft_filter_ccc.h>
33 gri_fft_filter_ccc::gri_fft_filter_ccc (int decimation, const std::vector<gr_complex> &taps)
34 : d_fftsize(-1), d_decimation(decimation), d_fwdfft(0), d_invfft(0)
39 gri_fft_filter_ccc::~gri_fft_filter_ccc ()
47 print_vector_complex(const std::string label, const std::vector<gr_complex> &x)
50 for (unsigned i = 0; i < x.size(); i++)
51 std::cout << x[i] << " ";
58 * determines d_ntaps, d_nsamples, d_fftsize, d_xformed_taps
61 gri_fft_filter_ccc::set_taps (const std::vector<gr_complex> &taps)
64 compute_sizes(taps.size());
66 d_tail.resize(tailsize());
67 for (i = 0; i < tailsize(); i++)
70 gr_complex *in = d_fwdfft->get_inbuf();
71 gr_complex *out = d_fwdfft->get_outbuf();
73 float scale = 1.0 / d_fftsize;
75 // Compute forward xform of taps.
76 // Copy taps into first ntaps slots, then pad with zeros
77 for (i = 0; i < d_ntaps; i++)
78 in[i] = taps[i] * scale;
80 for (; i < d_fftsize; i++)
83 d_fwdfft->execute(); // do the xform
85 // now copy output to d_xformed_taps
86 for (i = 0; i < d_fftsize; i++)
87 d_xformed_taps[i] = out[i];
92 // determine and set d_ntaps, d_nsamples, d_fftsize
95 gri_fft_filter_ccc::compute_sizes(int ntaps)
97 int old_fftsize = d_fftsize;
99 d_fftsize = (int) (2 * pow(2.0, ceil(log(ntaps) / log(2))));
100 d_nsamples = d_fftsize - d_ntaps + 1;
103 fprintf(stderr, "gri_fft_filter_ccc: ntaps = %d, fftsize = %d, nsamples = %d\n",
104 d_ntaps, d_fftsize, d_nsamples);
106 assert(d_fftsize == d_ntaps + d_nsamples -1 );
108 if (d_fftsize != old_fftsize){ // compute new plans
111 d_fwdfft = new gri_fft_complex(d_fftsize, true);
112 d_invfft = new gri_fft_complex(d_fftsize, false);
113 d_xformed_taps.resize(d_fftsize);
118 gri_fft_filter_ccc::filter (int nitems, const gr_complex *input, gr_complex *output)
122 int ninput_items = nitems * d_decimation;
124 for (int i = 0; i < ninput_items; i += d_nsamples){
126 memcpy(d_fwdfft->get_inbuf(), &input[i], d_nsamples * sizeof(gr_complex));
128 for (j = d_nsamples; j < d_fftsize; j++)
129 d_fwdfft->get_inbuf()[j] = 0;
131 d_fwdfft->execute(); // compute fwd xform
133 gr_complex *a = d_fwdfft->get_outbuf();
134 gr_complex *b = &d_xformed_taps[0];
135 gr_complex *c = d_invfft->get_inbuf();
137 for (j = 0; j < d_fftsize; j++) // filter in the freq domain
140 d_invfft->execute(); // compute inv xform
142 // add in the overlapping tail
144 for (j = 0; j < tailsize(); j++)
145 d_invfft->get_outbuf()[j] += d_tail[j];
147 // copy nsamples to output
149 while (j < d_nsamples) {
150 *output++ = d_invfft->get_outbuf()[j];
153 dec_ctr = (j - d_nsamples);
156 memcpy(&d_tail[0], d_invfft->get_outbuf() + d_nsamples,
157 tailsize() * sizeof(gr_complex));
160 assert(dec_ctr == 0);