tinymodem::OliviaCodec Class Reference

The forward error correction of Olivia and Contestia (as in fldigi): each character of a block of bitsPerSymbol() characters is a Walsh-Hadamard code word of 64 (Contestia: 32) bits, which is scrambled and spread diagonally over the 64 (32) symbols of the block. More...

#include <Olivia.h>

Public Member Functions
void	begin (int bits_per_symbol, bool is_contestia)
bool	isSkipped (uint8_t ch) const
void	encodeBlock (const uint8_t *chars, uint8_t *symbols)
	Encodes bits characters into block_len symbols (binary, not Gray coded).
uint8_t	decodeChar (const int8_t *soft, int b, float &peak, float &noise)
int	blockLen () const

Static Public Member Functions
static uint8_t	grayCode (uint8_t binary)
static uint8_t	binaryCode (uint8_t gray)

Protected Member Functions
uint64_t	scramblingCode () const
int	shift () const
uint8_t	encodeChar (uint8_t ch) const
uint8_t	decodeChar (uint8_t ch) const

Static Protected Member Functions
template<class T>
static void	fhtTransform (T *data, int len)
	fast Hadamard transform (fldigi FHT)
template<class T>
static void	ifht (T *data, int len)
	inverse fast Hadamard transform (fldigi IFHT)

Protected Attributes
int	bits = 5
int	block_len = 64
bool	contestia = false

Detailed Description

The forward error correction of Olivia and Contestia (as in fldigi): each character of a block of bitsPerSymbol() characters is a Walsh-Hadamard code word of 64 (Contestia: 32) bits, which is scrambled and spread diagonally over the 64 (32) symbols of the block.

Copyright

GPLv3

Member Function Documentation

begin()

void tinymodem::OliviaCodec::begin ( int bits_per_symbol, bool is_contestia )

inline

binaryCode()

uint8_t tinymodem::OliviaCodec::binaryCode ( uint8_t gray )

inlinestatic

blockLen()

int tinymodem::OliviaCodec::blockLen ( ) const

inline

decodeChar() [1/2]

uint8_t tinymodem::OliviaCodec::decodeChar ( const int8_t * soft, int b, float & peak, float & noise )

inline

Decodes the character b from the soft bits of a block: soft[t * bits + k] is bit k of symbol t (positive = 0). Provides the correlation peak and the energy of the other correlations.

decodeChar() [2/2]

uint8_t tinymodem::OliviaCodec::decodeChar ( uint8_t ch ) const

inlineprotected

encodeBlock()

void tinymodem::OliviaCodec::encodeBlock ( const uint8_t * chars, uint8_t * symbols )

inline

Encodes bits characters into block_len symbols (binary, not Gray coded).

encodeChar()

uint8_t tinymodem::OliviaCodec::encodeChar ( uint8_t ch ) const

inlineprotected

fhtTransform()

template<class T>

void tinymodem::OliviaCodec::fhtTransform ( T * data, int len )

inlinestaticprotected

fast Hadamard transform (fldigi FHT)

grayCode()

uint8_t tinymodem::OliviaCodec::grayCode ( uint8_t binary )

inlinestatic

ifht()

template<class T>

void tinymodem::OliviaCodec::ifht ( T * data, int len )

inlinestaticprotected

inverse fast Hadamard transform (fldigi IFHT)

isSkipped()

bool tinymodem::OliviaCodec::isSkipped ( uint8_t ch ) const

inline

true if the character is not transmitted (Contestia: '\r', which is replaced by '
')

scramblingCode()

uint64_t tinymodem::OliviaCodec::scramblingCode ( ) const

inlineprotected

shift()

int tinymodem::OliviaCodec::shift ( ) const

inlineprotected

Member Data Documentation

bits

int tinymodem::OliviaCodec::bits = 5

protected

block_len

int tinymodem::OliviaCodec::block_len = 64

protected

contestia

bool tinymodem::OliviaCodec::contestia = false

protected

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The documentation for this class was generated from the following file:

• src/modem/Olivia.h