Olivia and Contestia demodulator (compatible with fldigi): the PCM audio data is written to the decoder and the decoded characters are written to the output. The input can be 8, 16 or 32 bit signed samples with any number of channels (only OliviaConfig::channel is evaluated). More...

#include <OliviaDecoder.h>

Inheritance diagram for tinymodem::OliviaDecoder:

[legend]

Collaboration diagram for tinymodem::OliviaDecoder:

[legend]

Public Member Functions
	OliviaDecoder ()=default
	OliviaDecoder (Print &out)
OliviaConfig	defaultConfig ()
	Provides a default configuration: olivia-32-1000.
void	setAudioInfo (audio_tools::AudioInfo info) override
	Defines the format of the input audio data.
audio_tools::AudioInfo	audioInfo () override
bool	begin (OliviaConfig config)
	Starts the processing with the indicated configuration.
bool	begin () override
void	end () override
	Processes the remaining samples and reports the end of the carrier.
void	flush () override
	Processes the remaining samples (e.g. at the end of the input).
size_t	write (const uint8_t *data, size_t len) override
	Provide PCM data to the decoder.
bool	isCarrier () override
	true while a transmission is received
bool	isFinished () override
	true if the decoding was stopped (rx_one)
float	signalToNoise ()
	Signal to noise ratio of the synchronizer.
float	frequencyOffset ()
	Frequency offset of the received signal in Hz.
OliviaConfig &	config ()
	The configuration which was provided in begin().
	operator bool () override
Public Member Functions inherited from tinymodem::ModemDecoder
void	setStatusOutput (Print &out)
	Defines the output for the ### CARRIER / ### NOCARRIER messages.
void	setQuiet (bool quiet)
	Suppresses the status messages.
const char *	mime () override

Protected Member Functions
void	resetState ()
void	resetSync ()
	Forgets the timing and frequency of the last transmission.
float	noise ()
	uniform random value in the range -0.5 to 0.5
void	addSample8k (float x)
void	processSlice ()
	FFT over the last symbol_len samples and decoding of all offsets.
void	softDecode (const float tone_energy, int8_t out)
	Soft bits of a symbol from the tone energies (like fldigi).
int	repeatedSymbols (const int8_t *block)
	Number of symbols which are equal to the previous symbol (hard decision).
void	linearize (const int8_t buffer, int8_t block)
	Copies the circular soft bit buffer: the oldest symbol first.
void	evaluateBlock ()
	Provides the best block if the signal to noise ratio is sufficient.
void	outputChar (uint8_t ch)
void	startOfCarrier ()
void	endOfCarrier ()
Protected Member Functions inherited from tinymodem::ModemDecoder
void	status (const char *fmt,...)

Protected Attributes
OliviaConfig	cfg
bool	is_active = false
bool	is_finished = false
PcmInput	input
SampleRateConverter	converter
OliviaCodec	codec
SimpleFFT	fft
uint32_t	noise_seed = 1
int	bits = 5
int	tones = 32
int	block_len = 64
int	symbol_len = 512
int	margin = 8
int	offsets = 17
int	phases = 128
int	first_bin = 0
int	width = 0
audio_tools::Vector< float >	samples
audio_tools::Vector< float >	window
audio_tools::Vector< float >	fft_re
audio_tools::Vector< float >	fft_im
audio_tools::Vector< float >	energy
int	sample_pos = 0
int	slice_countdown = 0
int	slice = 0
audio_tools::Vector< int8_t >	soft
int	soft_pos = 0
audio_tools::Vector< float >	sync_signal
audio_tools::Vector< float >	sync_noise
audio_tools::Vector< uint64_t >	blocks
audio_tools::Vector< float >	block_snr
int	phase = 0
float	best_signal = 0
float	best_noise = 0
int	best_phase = 0
int	best_offset = 0
float	snr = 0
bool	carrier = false
bool	escape = false
unsigned	ndata = 0
unsigned	nblocks = 0
float	snr_total = 0
Protected Attributes inherited from tinymodem::ModemDecoder
Print *	p_status = nullptr
bool	is_quiet = false

Static Protected Attributes
static constexpr int	SLICES = 2
static constexpr float	BLOCK_THRESHOLD = 1.0f
	minimum signal to noise ratio of a block relative to the sync threshold

Detailed Description

Olivia and Contestia demodulator (compatible with fldigi): the PCM audio data is written to the decoder and the decoded characters are written to the output. The input can be 8, 16 or 32 bit signed samples with any number of channels (only OliviaConfig::channel is evaluated).

The input is converted to 8000 Hz. Twice per symbol the tone energies are measured with an FFT and converted to soft bits for each possible frequency offset (+/- OliviaConfig::sync_margin FFT bins). For each time slice and frequency offset the last FEC block is decoded after every symbol. The synchronizer integrates the signal and noise of the decoded blocks over OliviaConfig::sync_integration blocks and selects the block timing and the frequency offset with the strongest signal. A block is provided if its signal to noise ratio is above OliviaConfig::sync_threshold. The idle character 0 is not provided.

Memory: about (2 * sync_margin + 1) * 3 * symbolsPerBlock() * (bits per symbol + 16) bytes plus 20 * symbolLen() bytes, e.g. 30 kB for olivia-32-1000.

Copyright: GPLv3

Constructor & Destructor Documentation

◆ OliviaDecoder() [1/2]

tinymodem::OliviaDecoder::OliviaDecoder ( )

default

◆ OliviaDecoder() [2/2]

tinymodem::OliviaDecoder::OliviaDecoder ( Print & out )

inline

Member Function Documentation

◆ addSample8k()

void tinymodem::OliviaDecoder::addSample8k ( float x )

inlineprotected

◆ audioInfo()

audio_tools::AudioInfo tinymodem::OliviaDecoder::audioInfo ( )

inlineoverride

◆ begin() [1/2]

bool tinymodem::OliviaDecoder::begin ( )

inlineoverride

◆ begin() [2/2]

bool tinymodem::OliviaDecoder::begin ( OliviaConfig config )

inline

Starts the processing with the indicated configuration.

◆ config()

OliviaConfig & tinymodem::OliviaDecoder::config ( )

inline

The configuration which was provided in begin().

◆ defaultConfig()

OliviaConfig tinymodem::OliviaDecoder::defaultConfig ( )

inline

Provides a default configuration: olivia-32-1000.

◆ end()

void tinymodem::OliviaDecoder::end ( )

inlineoverride

Processes the remaining samples and reports the end of the carrier.

◆ endOfCarrier()

void tinymodem::OliviaDecoder::endOfCarrier ( )

inlineprotected

◆ evaluateBlock()

void tinymodem::OliviaDecoder::evaluateBlock ( )

inlineprotected

Provides the best block if the signal to noise ratio is sufficient.

◆ flush()

void tinymodem::OliviaDecoder::flush ( )

inlineoverridevirtual

Processes the remaining samples (e.g. at the end of the input).

Implements tinymodem::ModemDecoder.

◆ frequencyOffset()

float tinymodem::OliviaDecoder::frequencyOffset ( )

inline

Frequency offset of the received signal in Hz.

◆ isCarrier()

bool tinymodem::OliviaDecoder::isCarrier ( )

inlineoverridevirtual

true while a transmission is received

Implements tinymodem::ModemDecoder.

◆ isFinished()

bool tinymodem::OliviaDecoder::isFinished ( )

inlineoverridevirtual

true if the decoding was stopped (rx_one)

Implements tinymodem::ModemDecoder.

◆ linearize()

void tinymodem::OliviaDecoder::linearize	(	const int8_t *	buffer,
		int8_t *	block )

inlineprotected

Copies the circular soft bit buffer: the oldest symbol first.

◆ noise()

float tinymodem::OliviaDecoder::noise ( )

inlineprotected

uniform random value in the range -0.5 to 0.5

◆ operator bool()

tinymodem::OliviaDecoder::operator bool ( )

inlineoverride

◆ outputChar()

void tinymodem::OliviaDecoder::outputChar ( uint8_t ch )

inlineprotected

◆ processSlice()

void tinymodem::OliviaDecoder::processSlice ( )

inlineprotected

FFT over the last symbol_len samples and decoding of all offsets.

◆ repeatedSymbols()

int tinymodem::OliviaDecoder::repeatedSymbols ( const int8_t * block )

inlineprotected

Number of symbols which are equal to the previous symbol (hard decision).

◆ resetState()

void tinymodem::OliviaDecoder::resetState ( )

inlineprotected

◆ resetSync()

void tinymodem::OliviaDecoder::resetSync ( )

inlineprotected

Forgets the timing and frequency of the last transmission.

◆ setAudioInfo()

void tinymodem::OliviaDecoder::setAudioInfo ( audio_tools::AudioInfo info )

inlineoverride

Defines the format of the input audio data.

◆ signalToNoise()

float tinymodem::OliviaDecoder::signalToNoise ( )

inline

Signal to noise ratio of the synchronizer.

◆ softDecode()

void tinymodem::OliviaDecoder::softDecode	(	const float *	tone_energy,
		int8_t *	out )

inlineprotected

Soft bits of a symbol from the tone energies (like fldigi).

◆ startOfCarrier()

void tinymodem::OliviaDecoder::startOfCarrier ( )

inlineprotected

◆ write()

size_t tinymodem::OliviaDecoder::write	(	const uint8_t *	data,
		size_t	len )

inlineoverride

Provide PCM data to the decoder.

Member Data Documentation

◆ best_noise

float tinymodem::OliviaDecoder::best_noise = 0

protected

◆ best_offset

int tinymodem::OliviaDecoder::best_offset = 0

protected

◆ best_phase

int tinymodem::OliviaDecoder::best_phase = 0

protected

◆ best_signal

float tinymodem::OliviaDecoder::best_signal = 0

protected

◆ bits

int tinymodem::OliviaDecoder::bits = 5

protected

◆ block_len

int tinymodem::OliviaDecoder::block_len = 64

protected

◆ block_snr

audio_tools::Vector<float> tinymodem::OliviaDecoder::block_snr

protected

◆ BLOCK_THRESHOLD

float tinymodem::OliviaDecoder::BLOCK_THRESHOLD = 1.0f

staticconstexprprotected

minimum signal to noise ratio of a block relative to the sync threshold

◆ blocks

audio_tools::Vector<uint64_t> tinymodem::OliviaDecoder::blocks

protected

◆ carrier

bool tinymodem::OliviaDecoder::carrier = false

protected

◆ cfg

OliviaConfig tinymodem::OliviaDecoder::cfg

protected

◆ codec

OliviaCodec tinymodem::OliviaDecoder::codec

protected

◆ converter

SampleRateConverter tinymodem::OliviaDecoder::converter

protected

◆ energy

audio_tools::Vector<float> tinymodem::OliviaDecoder::energy

protected

◆ escape

bool tinymodem::OliviaDecoder::escape = false

protected

◆ fft

SimpleFFT tinymodem::OliviaDecoder::fft

protected

◆ fft_im

audio_tools::Vector<float> tinymodem::OliviaDecoder::fft_im

protected

◆ fft_re

audio_tools::Vector<float> tinymodem::OliviaDecoder::fft_re

protected

◆ first_bin

int tinymodem::OliviaDecoder::first_bin = 0

protected

◆ input

PcmInput tinymodem::OliviaDecoder::input

protected

◆ is_active

bool tinymodem::OliviaDecoder::is_active = false

protected

◆ is_finished

bool tinymodem::OliviaDecoder::is_finished = false

protected

◆ margin

int tinymodem::OliviaDecoder::margin = 8

protected

◆ nblocks

unsigned tinymodem::OliviaDecoder::nblocks = 0

protected

◆ ndata

unsigned tinymodem::OliviaDecoder::ndata = 0

protected

◆ noise_seed

uint32_t tinymodem::OliviaDecoder::noise_seed = 1

protected

◆ offsets

int tinymodem::OliviaDecoder::offsets = 17

protected

◆ phase

int tinymodem::OliviaDecoder::phase = 0

protected

◆ phases

int tinymodem::OliviaDecoder::phases = 128

protected

◆ sample_pos

int tinymodem::OliviaDecoder::sample_pos = 0

protected

◆ samples

audio_tools::Vector<float> tinymodem::OliviaDecoder::samples

protected

◆ slice

int tinymodem::OliviaDecoder::slice = 0

protected

◆ slice_countdown

int tinymodem::OliviaDecoder::slice_countdown = 0

protected

◆ SLICES

int tinymodem::OliviaDecoder::SLICES = 2

staticconstexprprotected

◆ snr

float tinymodem::OliviaDecoder::snr = 0

protected

◆ snr_total

float tinymodem::OliviaDecoder::snr_total = 0

protected

◆ soft

audio_tools::Vector<int8_t> tinymodem::OliviaDecoder::soft

protected

◆ soft_pos

int tinymodem::OliviaDecoder::soft_pos = 0

protected

◆ symbol_len

int tinymodem::OliviaDecoder::symbol_len = 512

protected

◆ sync_noise

audio_tools::Vector<float> tinymodem::OliviaDecoder::sync_noise

protected

◆ sync_signal

audio_tools::Vector<float> tinymodem::OliviaDecoder::sync_signal

protected

◆ tones

int tinymodem::OliviaDecoder::tones = 32

protected

◆ width

int tinymodem::OliviaDecoder::width = 0

protected

◆ window

audio_tools::Vector<float> tinymodem::OliviaDecoder::window

protected

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

src/modem/OliviaDecoder.h

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ OliviaDecoder() [1/2]

◆ OliviaDecoder() [2/2]

Member Function Documentation

◆ addSample8k()

◆ audioInfo()

◆ begin() [1/2]

◆ begin() [2/2]

◆ config()

◆ defaultConfig()

◆ end()

◆ endOfCarrier()

◆ evaluateBlock()

◆ flush()

◆ frequencyOffset()

◆ isCarrier()

◆ isFinished()

◆ linearize()

◆ noise()

◆ operator bool()

◆ outputChar()

◆ processSlice()

◆ repeatedSymbols()

◆ resetState()

◆ resetSync()

◆ setAudioInfo()

◆ signalToNoise()

◆ softDecode()

◆ startOfCarrier()

◆ write()

Member Data Documentation

◆ best_noise

◆ best_offset

◆ best_phase

◆ best_signal

◆ bits

◆ block_len

◆ block_snr

◆ BLOCK_THRESHOLD

◆ blocks

◆ carrier

◆ cfg

◆ codec

◆ converter

◆ energy

◆ escape

◆ fft

◆ fft_im

◆ fft_re

◆ first_bin

◆ input

◆ is_active

◆ is_finished

◆ margin

◆ nblocks

◆ ndata

◆ noise_seed

◆ offsets

◆ phase

◆ phases

◆ sample_pos

◆ samples

◆ slice

◆ slice_countdown

◆ SLICES

◆ snr

◆ snr_total

◆ soft

◆ soft_pos

◆ symbol_len

◆ sync_noise

◆ sync_signal

◆ tones

◆ width

◆ window