Morse code demodulator (CW): the PCM audio data is written to the decoder and the decoded characters (upper case) are written to the output. The input can be 8, 16 or 32 bit signed samples with any number of channels (only MorseConfig::channel is evaluated). More...

#include <MorseDecoder.h>

Inheritance diagram for tinymodem::MorseDecoder:

[legend]

Collaboration diagram for tinymodem::MorseDecoder:

[legend]

Public Member Functions
	MorseDecoder ()=default
	MorseDecoder (Print &out)
MorseConfig	defaultConfig ()
	Provides a default configuration: International Morse code, 20 wpm.
void	setAudioInfo (audio_tools::AudioInfo info) override
	Defines the format of the input audio data.
audio_tools::AudioInfo	audioInfo () override
bool	begin (MorseConfig 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	wpm ()
	Current speed of the sender in words per minute.
MorseConfig &	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 ()
float	noise ()
	uniform random value in the range -0.5 to 0.5
void	addSample (float x, bool add_noise)
void	recalculate ()
	Avoids the accumulation of rounding errors.
void	processBlock (float level)
	On/off decision of one block with the level of the tone.
void	endOfMark (float raw_length)
void	endOfSpace (float raw_length)
void	checkSpace (float raw_length)
	Ends the character, the word or the transmission during a space.
void	finishCharacter ()
void	output (char ch)
void	startOfCarrier ()
void	endOfCarrier ()
Protected Member Functions inherited from tinymodem::ModemDecoder
void	status (const char *fmt,...)

Protected Attributes
MorseConfig	cfg
bool	is_active = false
bool	is_finished = false
PcmInput	input
uint32_t	noise_seed = 1
int	block = 96
int	window = 480
int	count = 0
audio_tools::Vector< float >	history
int	pos = 0
float	sum_i = 0
float	sum_q = 0
float	re = 1
float	im = 0
float	step_re = 1
float	step_im = 0
uint32_t	sample_count = 0
float	signal_level = 0
float	noise_level = 0
float	noise_mean = 0
bool	first_block = true
bool	tone_on = false
int	pending = 0
float	duration = 0
float	unit = 0.06f
float	bias = 0
float	last_mark = 0
char	last_element = 0
bool	carrier = false
bool	word_pending = false
char	code [MAX_CODE+1]
int	code_len = 0
unsigned	ndata = 0
Protected Attributes inherited from tinymodem::ModemDecoder
Print *	p_status = nullptr
bool	is_quiet = false

Static Protected Attributes
static constexpr float	BLOCK_SEC = 0.002f
static constexpr float	WINDOW_UNITS = 0.5f
	length of the measurement window in units
static constexpr float	DEBOUNCE_UNITS = 0.3f
	changes which are shorter than this (in units) are ignored
static constexpr int	MAX_CODE = 16
static constexpr float	MIN_SNR = 5.0f
	min ratio of the tone level to the average noise level

Detailed Description

Morse code demodulator (CW): the PCM audio data is written to the decoder and the decoded characters (upper case) are written to the output. The input can be 8, 16 or 32 bit signed samples with any number of channels (only MorseConfig::channel is evaluated).

The level of the tone is measured with a mixer and a sliding sum over half a dot, every 2 ms. The tone is on when the level is above the middle between the signal and the noise level (with hysteresis), and short changes are ignored. The length of the marks and spaces in units provides the dots and dashes and the spaces between the elements, characters and words. The length of a unit adapts to the speed of the sender. The rise and fall time of the tone shortens the marks and lengthens the spaces by the same amount: this is measured with the dots and the following element spaces (both are 1 unit) and corrected.

A transmission ends after MorseConfig::rx_timeout_units without a tone: this is reported with ### NOCARRIER.

Copyright: GPLv3

Constructor & Destructor Documentation

◆ MorseDecoder() [1/2]

tinymodem::MorseDecoder::MorseDecoder ( )

default

◆ MorseDecoder() [2/2]

tinymodem::MorseDecoder::MorseDecoder ( Print & out )

inline

Member Function Documentation

◆ addSample()

void tinymodem::MorseDecoder::addSample	(	float	x,
		bool	add_noise )

inlineprotected

◆ audioInfo()

audio_tools::AudioInfo tinymodem::MorseDecoder::audioInfo ( )

inlineoverride

◆ begin() [1/2]

bool tinymodem::MorseDecoder::begin ( )

inlineoverride

◆ begin() [2/2]

bool tinymodem::MorseDecoder::begin ( MorseConfig config )

inline

Starts the processing with the indicated configuration.

◆ checkSpace()

void tinymodem::MorseDecoder::checkSpace ( float raw_length )

inlineprotected

Ends the character, the word or the transmission during a space.

◆ config()

MorseConfig & tinymodem::MorseDecoder::config ( )

inline

The configuration which was provided in begin().

◆ defaultConfig()

MorseConfig tinymodem::MorseDecoder::defaultConfig ( )

inline

Provides a default configuration: International Morse code, 20 wpm.

◆ end()

void tinymodem::MorseDecoder::end ( )

inlineoverride

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

◆ endOfCarrier()

void tinymodem::MorseDecoder::endOfCarrier ( )

inlineprotected

◆ endOfMark()

void tinymodem::MorseDecoder::endOfMark ( float raw_length )

inlineprotected

◆ endOfSpace()

void tinymodem::MorseDecoder::endOfSpace ( float raw_length )

inlineprotected

◆ finishCharacter()

void tinymodem::MorseDecoder::finishCharacter ( )

inlineprotected

◆ flush()

void tinymodem::MorseDecoder::flush ( )

inlineoverridevirtual

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

Implements tinymodem::ModemDecoder.

◆ isCarrier()

bool tinymodem::MorseDecoder::isCarrier ( )

inlineoverridevirtual

true while a transmission is received

Implements tinymodem::ModemDecoder.

◆ isFinished()

bool tinymodem::MorseDecoder::isFinished ( )

inlineoverridevirtual

true if the decoding was stopped (rx_one)

Implements tinymodem::ModemDecoder.

◆ noise()

float tinymodem::MorseDecoder::noise ( )

inlineprotected

uniform random value in the range -0.5 to 0.5

◆ operator bool()

tinymodem::MorseDecoder::operator bool ( )

inlineoverride

◆ output()

void tinymodem::MorseDecoder::output ( char ch )

inlineprotected

◆ processBlock()

void tinymodem::MorseDecoder::processBlock ( float level )

inlineprotected

On/off decision of one block with the level of the tone.

◆ recalculate()

void tinymodem::MorseDecoder::recalculate ( )

inlineprotected

Avoids the accumulation of rounding errors.

◆ resetState()

void tinymodem::MorseDecoder::resetState ( )

inlineprotected

◆ setAudioInfo()

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

inlineoverride

Defines the format of the input audio data.

◆ startOfCarrier()

void tinymodem::MorseDecoder::startOfCarrier ( )

inlineprotected

◆ wpm()

float tinymodem::MorseDecoder::wpm ( )

inline

Current speed of the sender in words per minute.

◆ write()

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

inlineoverride

Provide PCM data to the decoder.

Member Data Documentation

◆ bias

float tinymodem::MorseDecoder::bias = 0

protected

◆ block

int tinymodem::MorseDecoder::block = 96

protected

◆ BLOCK_SEC

float tinymodem::MorseDecoder::BLOCK_SEC = 0.002f

staticconstexprprotected

◆ carrier

bool tinymodem::MorseDecoder::carrier = false

protected

◆ cfg

MorseConfig tinymodem::MorseDecoder::cfg

protected

◆ code

char tinymodem::MorseDecoder::code[MAX_CODE+1]

protected

◆ code_len

int tinymodem::MorseDecoder::code_len = 0

protected

◆ count

int tinymodem::MorseDecoder::count = 0

protected

◆ DEBOUNCE_UNITS

float tinymodem::MorseDecoder::DEBOUNCE_UNITS = 0.3f

staticconstexprprotected

changes which are shorter than this (in units) are ignored

◆ duration

float tinymodem::MorseDecoder::duration = 0

protected

◆ first_block

bool tinymodem::MorseDecoder::first_block = true

protected

◆ history

audio_tools::Vector<float> tinymodem::MorseDecoder::history

protected

◆ im

float tinymodem::MorseDecoder::im = 0

protected

◆ input

PcmInput tinymodem::MorseDecoder::input

protected

◆ is_active

bool tinymodem::MorseDecoder::is_active = false

protected

◆ is_finished

bool tinymodem::MorseDecoder::is_finished = false

protected

◆ last_element

char tinymodem::MorseDecoder::last_element = 0

protected

◆ last_mark

float tinymodem::MorseDecoder::last_mark = 0

protected

◆ MAX_CODE

int tinymodem::MorseDecoder::MAX_CODE = 16

staticconstexprprotected

◆ MIN_SNR

float tinymodem::MorseDecoder::MIN_SNR = 5.0f

staticconstexprprotected

min ratio of the tone level to the average noise level

◆ ndata

unsigned tinymodem::MorseDecoder::ndata = 0

protected

◆ noise_level

float tinymodem::MorseDecoder::noise_level = 0

protected

◆ noise_mean

float tinymodem::MorseDecoder::noise_mean = 0

protected

◆ noise_seed

uint32_t tinymodem::MorseDecoder::noise_seed = 1

protected

◆ pending

int tinymodem::MorseDecoder::pending = 0

protected

◆ pos

int tinymodem::MorseDecoder::pos = 0

protected

◆ re

float tinymodem::MorseDecoder::re = 1

protected

◆ sample_count

uint32_t tinymodem::MorseDecoder::sample_count = 0

protected

◆ signal_level

float tinymodem::MorseDecoder::signal_level = 0

protected

◆ step_im

float tinymodem::MorseDecoder::step_im = 0

protected

◆ step_re

float tinymodem::MorseDecoder::step_re = 1

protected

◆ sum_i

float tinymodem::MorseDecoder::sum_i = 0

protected

◆ sum_q

float tinymodem::MorseDecoder::sum_q = 0

protected

◆ tone_on

bool tinymodem::MorseDecoder::tone_on = false

protected

◆ unit

float tinymodem::MorseDecoder::unit = 0.06f

protected

◆ window

int tinymodem::MorseDecoder::window = 480

protected

◆ WINDOW_UNITS

float tinymodem::MorseDecoder::WINDOW_UNITS = 0.5f

staticconstexprprotected

length of the measurement window in units

◆ word_pending

bool tinymodem::MorseDecoder::word_pending = false

protected

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

src/modem/MorseDecoder.h

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ MorseDecoder() [1/2]

◆ MorseDecoder() [2/2]

Member Function Documentation

◆ addSample()

◆ audioInfo()

◆ begin() [1/2]

◆ begin() [2/2]

◆ checkSpace()

◆ config()

◆ defaultConfig()

◆ end()

◆ endOfCarrier()

◆ endOfMark()

◆ endOfSpace()

◆ finishCharacter()

◆ flush()

◆ isCarrier()

◆ isFinished()

◆ noise()

◆ operator bool()

◆ output()

◆ processBlock()

◆ recalculate()

◆ resetState()

◆ setAudioInfo()

◆ startOfCarrier()

◆ wpm()

◆ write()

Member Data Documentation

◆ bias

◆ block

◆ BLOCK_SEC

◆ carrier

◆ cfg

◆ code

◆ code_len

◆ count

◆ DEBOUNCE_UNITS

◆ duration

◆ first_block

◆ history

◆ im

◆ input

◆ is_active

◆ is_finished

◆ last_element

◆ last_mark

◆ MAX_CODE

◆ MIN_SNR

◆ ndata

◆ noise_level

◆ noise_mean

◆ noise_seed

◆ pending

◆ pos

◆ re

◆ sample_count

◆ signal_level

◆ step_im

◆ step_re

◆ sum_i

◆ sum_q

◆ tone_on

◆ unit

◆ window

◆ WINDOW_UNITS

◆ word_pending