Modulator Class Reference

Audio device which synthesizes JS8 waveform samples for TX. More...

#include <Modulator.h>

Inheritance diagram for Modulator:

Collaboration diagram for Modulator:

Public Types
enum class	State { Synchronizing , Active , Idle }
Public Types inherited from AudioDevice
enum	Channel { Mono , Left , Right , Both }
	Audio channel selection used by the device. More...

Public Member Functions
	Modulator (QObject *parent=nullptr)
	Construct a modulator instance.
bool	isIdle () const
	Whether the device is currently idle.
void	close () override
	Close the device and stop generating samples.
Q_SLOT void	setAudioFrequency (double const audioFrequency)
	Set the base audio frequency used for modulation.
Q_SLOT void	start (double audioFrequency, int submode, double tx_delay, SoundOutput *stream, Channel channel)
	Start transmission with the given parameters.
Q_SLOT void	stop (bool quick=false)
	Stop transmission.
Q_SLOT void	tune (bool state=true)
	Enter or leave tuning state.
Public Member Functions inherited from AudioDevice
bool	initialize (OpenMode mode, Channel channel)
	Initialize the device for the specified open mode and channel.
bool	isSequential () const override
	Whether this device exposes a sequential data stream.
size_t	bytesPerFrame () const
	Number of bytes per audio frame for the current channel setting.
Channel	channel () const
	Get the current channel selection used by this device.

Protected Member Functions
qint64	readData (char *, qint64) override
	Read data from the modulator.
qint64	writeData (char const *, qint64) override
qint64	bytesAvailable () const override
	Bytes available hint for QAudioSink; ensures Active state.
Protected Member Functions inherited from AudioDevice
	AudioDevice (QObject *parent=nullptr)
void	store (char const *source, size_t numFrames, qint16 *dest)
	Copy interleaved source samples into the destination buffer.
qint16 *	load (qint16 const sample, qint16 *dest)
	Expand a sample value into the output buffer for the active channel.

Additional Inherited Members
Static Public Member Functions inherited from AudioDevice
static char const *	toString (Channel c)
static Channel	fromString (QString const &str)
	Convert a channel label into an AudioDevice channel value.

Detailed Description

Audio device which synthesizes JS8 waveform samples for TX.

The Modulator implements a QIODevice audio source that produces PCM samples encoding an outgoing message. Output may be muted while keeping timing intact to allow resuming without disrupting the transmission schedule. The device is intended to run in a worker thread and is not generally safe to call from arbitrary threads.

Constructor & Destructor Documentation

Modulator()

Modulator::Modulator ( QObject * parent = nullptr )

inlineexplicit

Construct a modulator instance.

Parameters

parent

Optional parent QObject.

Member Function Documentation

bytesAvailable()

qint64 Modulator::bytesAvailable ( ) const

inlineoverrideprotected

Bytes available hint for QAudioSink; ensures Active state.

Qt audio backends require that a source report a minimum number of bytes available in order to transition the sink into the Active state and begin pulling data. Different Qt releases/platforms changed this behavior; to remain compatible we provide a conservative bytes-available hint here.

Note

Observed version/platform behavior:

• Windows: behavior change observed starting in Qt 6.4
• macOS: behavior change observed starting in Qt 6.8
• Linux: behavior change observed starting in Qt 6.9

See also

https://bugreports.qt.io/browse/QTBUG-108672

close()

void Modulator::close ( )

override

Close the device and stop generating samples.

Close the modulator.

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isIdle()

bool Modulator::isIdle ( ) const

inline

Whether the device is currently idle.

Returns

true when idle.

This accessor is thread-safe and can be queried from other threads.

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readData()

qint64 Modulator::readData ( char * data, qint64 maxSize )

overrideprotected

Read data from the modulator.

Parameters

data
maxSize

Returns

qint64

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setAudioFrequency()

Q_SLOT void Modulator::setAudioFrequency ( double const audioFrequency )

inline

Set the base audio frequency used for modulation.

Parameters

audioFrequency

Frequency in Hz.

Not thread-safe by itself; use Qt signals to invoke from other threads.

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start()

void Modulator::start	(	double	audioFrequency,
		int	submode,
		double	tx_delay,
		SoundOutput *	stream,
		Channel	channel )

Start transmission with the given parameters.

Start the modulation process.

Parameters

frequency
submode
txDelay
stream
channel

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stop()

void Modulator::stop

(

bool

quick = false

)

Stop transmission.

Stop the modulation process.

Parameters

quick	If true, perform a quick stop.
quickClose

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tune()

void Modulator::tune

(

bool

state = true

)

Enter or leave tuning state.

Set tuning mode.

Parameters

tuning

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

• JS8_Mode/Modulator.h
• JS8_Mode/Modulator.cpp