FSK modulator: converts the written characters into 16 bit PCM audio which is written to the defined output. The generated signal is compatible with minimodem –rx. More...

#include <FSKEncoder.h>

Inheritance diagram for tinymodem::FSKEncoder:

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Collaboration diagram for tinymodem::FSKEncoder:

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Public Member Functions
	FSKEncoder ()=default
	FSKEncoder (Print &out)
	FSKEncoder (audio_tools::SoundGenerator< int16_t > &generator)
	FSKEncoder (Print &out, audio_tools::SoundGenerator< int16_t > &generator)
ModemConfig	defaultConfig ()
	Provides a default configuration for a 1200 baud Bell 202 modem.
void	setAudioInfo (audio_tools::AudioInfo info) override
	Defines the sample rate and number of channels of the generated audio.
audio_tools::AudioInfo	audioInfo () override
bool	begin (ModemConfig config)
	Starts the processing with the indicated modem configuration.
bool	begin () override
void	end () override
size_t	write (const uint8_t *data, size_t len) override
	Modulates the characters.
bool	endTransmission (size_t silence_samples=0) override
bool	writeIdle (size_t nsamples) override
	Sends the idle (mark) tone for the indicated number of samples.
bool	isTransmitting () override
	true between the first character and endTransmission()
float	symbolRate () override
	Bits per second.
size_t	bitSamples ()
	Number of samples of one bit.
ModemConfig &	config ()
const ModemConfig &	activeConfig () const
	The active configuration with all derived values (e.g. frequencies).
	operator bool () override
Public Member Functions inherited from tinymodem::ModemEncoder
void	setOutput (Print &out) override
void	setGenerator (audio_tools::SoundGenerator< int16_t > &generator)
audio_tools::SoundGenerator< int16_t > &	getGenerator ()
	Provides the active tone generator.
void	writeSilence (size_t nsamples)
	Writes the indicated number of samples of silence.
void	writeTone (float freq, size_t nsamples)
	Writes a tone for the indicated number of samples.
void	flush ()
	Ends the transmission.
const char *	mime () override

Protected Member Functions
float	idleFreq ()
void	startTransmission ()
void	writeChar (uint8_t ch)
void	transmitFrame (uint64_t bits, bool msb_first)
void	tone (float freq, size_t nsamples)

Protected Attributes
ModemConfig	cfg
ModemConfig	active_cfg
AsciiCodec	ascii
BaudotCodec	baudot
DataCodec *	p_codec = &ascii
size_t	bit_nsamples = 0
int	transmitting = 0
bool	is_active = false
Protected Attributes inherited from tinymodem::ModemEncoder
ToneOutput	tones

Detailed Description

FSK modulator: converts the written characters into 16 bit PCM audio which is written to the defined output. The generated signal is compatible with minimodem –rx.

The tones are produced by a SoundGenerator<int16_t>. By default this is a FSKToneGenerator, which reproduces minimodem's signal. You can replace it with setGenerator(): the generator must change the frequency immediately and keep the phase continuous in setFrequency() - e.g. the AudioTools FastIntSineGenerator, which needs no floating point and is a good choice for MCUs without FPU. FloatSineGenerator, FastSineGenerator and SineFromTable are not suited. The generator's amplitude is full scale: ModemConfig::volume is applied by the encoder.

A transmission starts with leader (mark) bits, followed by the optional sync bytes and the data frames. Call endTransmission() (or flush()) to send the trailer bits when there is no more data to send.

Copyright: GPLv3

Constructor & Destructor Documentation

◆ FSKEncoder() [1/4]

tinymodem::FSKEncoder::FSKEncoder ( )

default

◆ FSKEncoder() [2/4]

tinymodem::FSKEncoder::FSKEncoder ( Print & out )

inline

◆ FSKEncoder() [3/4]

tinymodem::FSKEncoder::FSKEncoder ( audio_tools::SoundGenerator< int16_t > & generator )

inline

◆ FSKEncoder() [4/4]

tinymodem::FSKEncoder::FSKEncoder	(	Print &	out,
		audio_tools::SoundGenerator< int16_t > &	generator )

inline

Member Function Documentation

◆ activeConfig()

const ModemConfig & tinymodem::FSKEncoder::activeConfig ( ) const

inline

The active configuration with all derived values (e.g. frequencies).

◆ audioInfo()

audio_tools::AudioInfo tinymodem::FSKEncoder::audioInfo ( )

inlineoverride

◆ begin() [1/2]

bool tinymodem::FSKEncoder::begin ( )

inlineoverride

◆ begin() [2/2]

bool tinymodem::FSKEncoder::begin ( ModemConfig config )

inline

Starts the processing with the indicated modem configuration.

◆ bitSamples()

size_t tinymodem::FSKEncoder::bitSamples ( )

inline

Number of samples of one bit.

◆ config()

ModemConfig & tinymodem::FSKEncoder::config ( )

inline

The configuration which was provided in begin(): you can change it and call begin() again

◆ defaultConfig()

ModemConfig tinymodem::FSKEncoder::defaultConfig ( )

inline

Provides a default configuration for a 1200 baud Bell 202 modem.

◆ end()

void tinymodem::FSKEncoder::end ( )

inlineoverride

◆ endTransmission()

bool tinymodem::FSKEncoder::endTransmission ( size_t silence_samples = 0 )

inlineoverridevirtual

Sends the trailer bits (and optional silence) if we are transmitting: returns true if a transmission was ended.

Implements tinymodem::ModemEncoder.

◆ idleFreq()

float tinymodem::FSKEncoder::idleFreq ( )

inlineprotected

◆ isTransmitting()

bool tinymodem::FSKEncoder::isTransmitting ( )

inlineoverridevirtual

true between the first character and endTransmission()

Implements tinymodem::ModemEncoder.

◆ operator bool()

tinymodem::FSKEncoder::operator bool ( )

inlineoverride

◆ setAudioInfo()

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

inlineoverride

Defines the sample rate and number of channels of the generated audio.

◆ startTransmission()

void tinymodem::FSKEncoder::startTransmission ( )

inlineprotected

◆ symbolRate()

float tinymodem::FSKEncoder::symbolRate ( )

inlineoverridevirtual

Bits per second.

Implements tinymodem::ModemEncoder.

◆ tone()

void tinymodem::FSKEncoder::tone	(	float	freq,
		size_t	nsamples )

inlineprotected

◆ transmitFrame()

void tinymodem::FSKEncoder::transmitFrame	(	uint64_t	bits,
		bool	msb_first )

inlineprotected

◆ write()

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

inlineoverride

Modulates the characters.

◆ writeChar()

void tinymodem::FSKEncoder::writeChar ( uint8_t ch )

inlineprotected

◆ writeIdle()

bool tinymodem::FSKEncoder::writeIdle ( size_t nsamples )

inlineoverridevirtual

Sends the idle (mark) tone for the indicated number of samples.

Reimplemented from tinymodem::ModemEncoder.

Member Data Documentation

◆ active_cfg

ModemConfig tinymodem::FSKEncoder::active_cfg

protected

◆ ascii

AsciiCodec tinymodem::FSKEncoder::ascii

protected

◆ baudot

BaudotCodec tinymodem::FSKEncoder::baudot

protected

◆ bit_nsamples

size_t tinymodem::FSKEncoder::bit_nsamples = 0

protected

◆ cfg

ModemConfig tinymodem::FSKEncoder::cfg

protected

◆ is_active

bool tinymodem::FSKEncoder::is_active = false

protected

◆ p_codec

DataCodec* tinymodem::FSKEncoder::p_codec = &ascii

protected

◆ transmitting

int tinymodem::FSKEncoder::transmitting = 0

protected

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

src/modem/FSKEncoder.h

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ FSKEncoder() [1/4]

◆ FSKEncoder() [2/4]

◆ FSKEncoder() [3/4]

◆ FSKEncoder() [4/4]

Member Function Documentation

◆ activeConfig()

◆ audioInfo()

◆ begin() [1/2]

◆ begin() [2/2]

◆ bitSamples()

◆ config()

◆ defaultConfig()

◆ end()

◆ endTransmission()

◆ idleFreq()

◆ isTransmitting()

◆ operator bool()

◆ setAudioInfo()

◆ startTransmission()

◆ symbolRate()

◆ tone()

◆ transmitFrame()

◆ write()

◆ writeChar()

◆ writeIdle()

Member Data Documentation

◆ active_cfg

◆ ascii

◆ baudot

◆ bit_nsamples

◆ cfg

◆ is_active

◆ p_codec

◆ transmitting