3 * Copyright 2008 Free Software Foundation, Inc.
5 * GNU Radio is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 3, or (at your option)
10 * GNU Radio is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with GNU Radio; see the file COPYING. If not, write to
17 * the Free Software Foundation, Inc., 51 Franklin Street,
18 * Boston, MA 02110-1301, USA.
25 #include <gr_decode_ccsds_27_fb.h>
26 #include <gr_io_signature.h>
28 gr_decode_ccsds_27_fb_sptr
29 gr_make_decode_ccsds_27_fb()
31 return gr_decode_ccsds_27_fb_sptr(new gr_decode_ccsds_27_fb());
34 gr_decode_ccsds_27_fb::gr_decode_ccsds_27_fb()
35 : gr_sync_decimator("decode_ccsds_27_fb",
36 gr_make_io_signature(1, 1, sizeof(float)),
37 gr_make_io_signature(1, 1, sizeof(char)),
38 2*8) // Rate 1/2 code, unpacked to packed translation
42 float esn0 = RATE*pow(10.0, ebn0/10);
44 gen_met(d_mettab, 100, esn0, 0.0, 256);
45 viterbi_chunks_init(d_state0);
48 gr_decode_ccsds_27_fb::~gr_decode_ccsds_27_fb()
53 gr_decode_ccsds_27_fb::work(int noutput_items,
54 gr_vector_const_void_star &input_items,
55 gr_vector_void_star &output_items)
57 const float *in = (const float *)input_items[0];
58 unsigned char *out = (unsigned char *)output_items[0];
60 for (int i = 0; i < noutput_items*16; i++) {
61 // Translate and clip [-1.0..1.0] to [28..228]
62 float sample = in[i]*100.0+128.0;
65 else if (sample < 0.0)
67 unsigned char sym = (unsigned char)(floor(sample));
69 d_viterbi_in[d_count % 4] = sym;
70 if ((d_count % 4) == 3) {
71 // Every fourth symbol, perform butterfly operation
72 viterbi_butterfly2(d_viterbi_in, d_mettab, d_state0, d_state1);
74 // Every sixteenth symbol, read out a byte
75 if (d_count % 16 == 11) {
77 viterbi_get_output(d_state0, out++);
78 // printf("%li\n", *(out-1), metric);