GNU Radio C++ API Reference: ccsds_encoder.h Source File

| GNU Radio C++ API Reference 3.10.12.0 The Free & Open Software Radio Ecosystem |

Loading...
Searching...
No Matches
ccsds_encoder.h
Go to the documentation of this file.
1/* -*- c++ -*- */
2/*
3 * Copyright 2014 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
7 * SPDX-License-Identifier: GPL-3.0-or-later
8 *
9 */
10
11#ifndef INCLUDED_FEC_CCSDS_ENCODER_H
12#define INCLUDED_FEC_CCSDS_ENCODER_H
13
14#include <gnuradio/fec/api.h>
15#include <gnuradio/fec/cc_common.h>
16#include <gnuradio/fec/encoder.h>
17#include <map>
18#include <string>
19
20namespace gr {
21namespace fec {
22namespace code {
23
24/*!
25 * \brief CCSDS Encoding class for convolutional encoding with
26 * rate 1/2, K=7, and polynomials [109, 79].
27 * \ingroup error_coding_blk
28 *
29 * \details
30 *
31 * Uses Phil Karn's (KA9Q) implementation of the CCSDS encoder
32 * for rate 1/2, K=7, and CC polynomial [109, 79]. These are
33 * non-adjustable in this encoder. For an adjustable CC encoder
34 * where we can set the rate, constraint length, and polynomial,
35 * see gr::fec::code::cc_encoder.
36 *
37 * The encoder is set up with a number of bits per frame in the
38 * constructor. When not being used in a tagged stream mode,
39 * this encoder will only process frames of the length provided
40 * here. If used in a tagged stream block, this setting becomes
41 * the maximum allowable frame size that the block may process.
42 *
43 * The \p mode is a cc_mode_t that specifies how the convolutional
44 * encoder will behave and under what conditions.
45 *
46 * \li 'CC_STREAMING': mode expects an uninterrupted flow of
47 * samples into the encoder, and the output stream is
48 * continually encoded.
49 *
50 * \li 'CC_TERMINATED': is a mode designed for packet-based
51 * systems. This mode adds rate*(k-1) bits to the output as a
52 * way to help flush the decoder.
53 *
54 * \li 'CC_TAILBITING': is another packet-based method. Instead of
55 * adding bits onto the end of the packet, this mode will
56 * continue the code between the payloads of packets by
57 * pre-initializing the state of the new packet based on the
58 * state of the last packet for (k-1) bits.
59 *
60 * \li 'CC_TRUNCATED': a truncated code always resets the registers
61 * to the \p start_state between frames.
62 *
63 * A common convolutional encoder uses K=7, Rate=1/2,
64 * Polynomials=[109, 79]. This is the Voyager code from NASA:
65 * \li 109: b(1101101) --> 1 + x + x^3 + x^4 + x^6
66 * \li 79: b(1001111) --> 1 + x^3 + x^4 + x^5 + x^6
67 */
68 class FEC_API ccsds_encoder : virtual public generic_encoder
69{
70public:
71 /*!
72 * Build the CCSDS (rate=1/2, K=7, polys=[109,79]
73 * convolutional code FECAPI object.
74 *
75 * \param frame_size Number of bits per frame. If using in the
76 * tagged stream style, this is the maximum allowable
77 * number of bits per frame.
78 * \param start_state Initialization state of the shift register.
79 * \param mode cc_mode_t mode of the encoding.
80 */
81 static generic_encoder::sptr
82 make(int frame_size, int start_state = 0, cc_mode_t mode = CC_STREAMING);
83
84 /*!
85 * Sets the uncoded frame size to \p frame_size. If \p
86 * frame_size is greater than the value given to the
87 * constructor, the frame size will be capped by that initial
88 * value and this function will return false. Otherwise, it
89 * returns true.
90 */
91 bool set_frame_size(unsigned int frame_size) override = 0;
92
93 /*!
94 * Returns the coding rate of this encoder.
95 */
96 double rate() override = 0;
97};
98
99} /* namespace code */
100} /* namespace fec */
101} /* namespace gr */
102
103#endif /* INCLUDED_FEC_CCSDS_ENCODER_H */
cc_common.h
cc_mode_t
enum _cc_mode_t cc_mode_t
CC_STREAMING
@ CC_STREAMING
Definition cc_common.h:17
gr::fec::code::ccsds_encoder
CCSDS Encoding class for convolutional encoding with rate 1/2, K=7, and polynomials [109,...
Definition ccsds_encoder.h:69
gr::fec::code::ccsds_encoder::rate
double rate() override=0
gr::fec::code::ccsds_encoder::make
static generic_encoder::sptr make(int frame_size, int start_state=0, cc_mode_t mode=CC_STREAMING)
gr::fec::code::ccsds_encoder::set_frame_size
bool set_frame_size(unsigned int frame_size) override=0
gr::fec::generic_encoder::sptr
std::shared_ptr< generic_encoder > sptr
Definition generic_encoder.h:37
gr::fec::generic_encoder::generic_encoder
generic_encoder(void)
Definition generic_encoder.h:119
api.h
FEC_API
#define FEC_API
Definition gr-fec/include/gnuradio/fec/api.h:18
encoder.h
gr::fec::code
Definition cc_decoder.h:22
gr::fec
Definition async_decoder.h:20
gr
GNU Radio logging wrapper.
Definition basic_block.h:29