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ccsds_encoder.h
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/* -*- c++ -*- */
/*
* Copyright 2014 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_FEC_CCSDS_ENCODER_H
#define INCLUDED_FEC_CCSDS_ENCODER_H
#include <gnuradio/fec/api.h>
#include <gnuradio/fec/cc_common.h>
#include <gnuradio/fec/encoder.h>
#include <map>
#include <string>
namespace gr {
namespace fec {
namespace code {
/*!
* \brief CCSDS Encoding class for convolutional encoding with
* rate 1/2, K=7, and polynomials [109, 79].
* \ingroup error_coding_blk
*
* \details
*
* Uses Phil Karn's (KA9Q) implementation of the CCSDS encoder
* for rate 1/2, K=7, and CC polynomial [109, 79]. These are
* non-adjustable in this encoder. For an adjustable CC encoder
* where we can set the rate, constraint length, and polynomial,
* see gr::fec::code::cc_encoder.
*
* The encoder is set up with a number of bits per frame in the
* constructor. When not being used in a tagged stream mode,
* this encoder will only process frames of the length provided
* here. If used in a tagged stream block, this setting becomes
* the maximum allowable frame size that the block may process.
*
* The \p mode is a cc_mode_t that specifies how the convolutional
* encoder will behave and under what conditions.
*
* \li 'CC_STREAMING': mode expects an uninterrupted flow of
* samples into the encoder, and the output stream is
* continually encoded.
*
* \li 'CC_TERMINATED': is a mode designed for packet-based
* systems. This mode adds rate*(k-1) bits to the output as a
* way to help flush the decoder.
*
* \li 'CC_TAILBITING': is another packet-based method. Instead of
* adding bits onto the end of the packet, this mode will
* continue the code between the payloads of packets by
* pre-initializing the state of the new packet based on the
* state of the last packet for (k-1) bits.
*
* \li 'CC_TRUNCATED': a truncated code always resets the registers
* to the \p start_state between frames.
*
* A common convolutional encoder uses K=7, Rate=1/2,
* Polynomials=[109, 79]. This is the Voyager code from NASA:
* \li 109: b(1101101) --> 1 + x + x^3 + x^4 + x^6
* \li 79: b(1001111) --> 1 + x^3 + x^4 + x^5 + x^6
*/
class FEC_API ccsds_encoder : virtual public generic_encoder
{
public:
/*!
* Build the CCSDS (rate=1/2, K=7, polys=[109,79]
* convolutional code FECAPI object.
*
* \param frame_size Number of bits per frame. If using in the
* tagged stream style, this is the maximum allowable
* number of bits per frame.
* \param start_state Initialization state of the shift register.
* \param mode cc_mode_t mode of the encoding.
*/
static generic_encoder::sptr
make(int frame_size, int start_state = 0, cc_mode_t mode = CC_STREAMING);
/*!
* Sets the uncoded frame size to \p frame_size. If \p
* frame_size is greater than the value given to the
* constructor, the frame size will be capped by that initial
* value and this function will return false. Otherwise, it
* returns true.
*/
bool set_frame_size(unsigned int frame_size) override = 0;
/*!
* Returns the coding rate of this encoder.
*/
double rate() override = 0;
};
} /* namespace code */
} /* namespace fec */
} /* namespace gr */
#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