1 /* -*- c++ -*- */
2 /*
3 * Copyright 2012,2014 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
10 * any later version.
11 *
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
21 */
22
23 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26
27 #include <gnuradio/filter/polyphase_filterbank.h>
28 #include <cstdio>
29
30 namespace gr {
31 namespace filter {
32 namespace kernel {
33
polyphase_filterbank(unsigned int nfilts,const std::vector<float> & taps,bool fft_forward)34 polyphase_filterbank::polyphase_filterbank(unsigned int nfilts,
35 const std::vector<float>& taps,
36 bool fft_forward)
37 : d_nfilts(nfilts)
38 {
39 d_fir_filters = std::vector<kernel::fir_filter_ccf*>(d_nfilts);
40 d_fft_filters = std::vector<kernel::fft_filter_ccf*>(d_nfilts);
41
42 // Create an FIR filter for each channel and zero out the taps
43 std::vector<float> vtaps(1, 0.0f);
44 for (unsigned int i = 0; i < d_nfilts; i++) {
45 d_fir_filters[i] = new kernel::fir_filter_ccf(1, vtaps);
46 d_fft_filters[i] = new kernel::fft_filter_ccf(1, vtaps);
47 }
48
49 // Now, actually set the filters' taps
50 set_taps(taps);
51
52 // Create the FFT to handle the output de-spinning of the channels
53 d_fft = new fft::fft_complex(d_nfilts, fft_forward);
54 }
55
~polyphase_filterbank()56 polyphase_filterbank::~polyphase_filterbank()
57 {
58 delete d_fft;
59 for (unsigned int i = 0; i < d_nfilts; i++) {
60 delete d_fir_filters[i];
61 delete d_fft_filters[i];
62 }
63 }
64
set_taps(const std::vector<float> & taps)65 void polyphase_filterbank::set_taps(const std::vector<float>& taps)
66 {
67 unsigned int i, j;
68 unsigned int ntaps = taps.size();
69 d_taps_per_filter = (unsigned int)ceil((double)ntaps / (double)d_nfilts);
70
71 // Create d_numchan vectors to store each channel's taps
72 d_taps.resize(d_nfilts);
73
74 // Make a vector of the taps plus fill it out with 0's to fill
75 // each polyphase filter with exactly d_taps_per_filter
76 std::vector<float> tmp_taps = taps;
77 while ((float)(tmp_taps.size()) < d_nfilts * d_taps_per_filter) {
78 tmp_taps.push_back(0.0);
79 }
80
81 // Partition the filter
82 for (i = 0; i < d_nfilts; i++) {
83 // Each channel uses all d_taps_per_filter with 0's if not enough taps to fill out
84 d_taps[i] = std::vector<float>(d_taps_per_filter, 0);
85 for (j = 0; j < d_taps_per_filter; j++) {
86 d_taps[i][j] = tmp_taps[i + j * d_nfilts];
87 }
88
89 // Set the filter taps for each channel
90 d_fir_filters[i]->set_taps(d_taps[i]);
91 d_fft_filters[i]->set_taps(d_taps[i]);
92 }
93 }
94
print_taps()95 void polyphase_filterbank::print_taps()
96 {
97 unsigned int i, j;
98 for (i = 0; i < d_nfilts; i++) {
99 printf("filter[%d]: [", i);
100 for (j = 0; j < d_taps_per_filter; j++) {
101 printf(" %.4e", d_taps[i][j]);
102 }
103 printf("]\n\n");
104 }
105 }
106
taps() const107 std::vector<std::vector<float>> polyphase_filterbank::taps() const { return d_taps; }
108
109 } /* namespace kernel */
110 } /* namespace filter */
111 } /* namespace gr */
112