PTones Class Reference

This class can be used to generate PCM data for tones (such as telephone calling tones and DTMF) at a sample rate of 8khz. More...

#include <dtmf.h>

Inheritance diagram for PTones:

Collaboration diagram for PTones:

Public Types
enum	{   MaxVolume = 100, DefaultSampleRate = 8000, MinFrequency = 30, MinModulation = 5,   SineScale = 1000 }
Public Types inherited from PObject
enum	Comparison { LessThan = -1, EqualTo = 0, GreaterThan = 1 }
	Result of the comparison operation performed by the Compare() function. More...

Public Member Functions
	PTones (unsigned masterVolume=MaxVolume, unsigned sampleRate=DefaultSampleRate)
	Create an empty tone buffer. More...
	PTones (const PString &descriptor, unsigned masterVolume=MaxVolume, unsigned sampleRate=DefaultSampleRate)
	Create a filled tone buffer using the specified descriptor. More...
bool	Generate (const PString &descriptor, unsigned sampleRate=0, unsigned masterVolume=0)
	Generate a tone using the specified descriptor. More...
bool	Generate (char operation, unsigned frequency1, unsigned frequency2, unsigned milliseconds, unsigned volume=MaxVolume)
	Generate a tone using the specified values. More...
bool	Write (PChannel &channel)
	Write tones to channel. More...
unsigned	GetSampleRate () const
	Get the sample rate for tones. More...
void	SetSampleRate (unsigned rate)
	Set sample rate for tones, note will clear tone buffer. More...
virtual PBoolean	SetSize (PINDEX newSize)
	Set the size of the array in elements. More...
Public Member Functions inherited from PScalarArray< T >
	PScalarArray (PINDEX initialSize=0)
	Construct a new dynamic array of elements of the specified type. More...
	PScalarArray (T const *buffer, PINDEX length, PBoolean dynamic=true)
	Construct a new dynamic array of elements of the specified type. More...
Public Member Functions inherited from PBaseArray< T >
	PBaseArray (PINDEX initialSize=0)
	Construct a new dynamic array of elements of the specified type. More...
	PBaseArray (T const *buffer, PINDEX length, PBoolean dynamic=true)
	Construct a new dynamic array of elements of the specified type. More...
virtual PObject *	Clone () const
	Clone the object. More...
PBoolean	SetAt (PINDEX index, T val)
	Set the specific element in the array. More...
T	GetAt (PINDEX index) const
	Get a value from the array. More...
void	Attach (const T *buffer, PINDEX bufferSize)
	Attach a pointer to a static block to the base array type. More...
T *	GetPointer (PINDEX minSize=0)
	Get a pointer to the internal array and assure that it is of at least the specified size. More...
T	operator[] (PINDEX index) const
	Get a value from the array. More...
T &	operator[] (PINDEX index)
	Get a reference to value from the array. More...
	operator T const * () const
	Get a pointer to the internal array. More...
PBoolean	Concatenate (const PBaseArray &array)
	Concatenate one array to the end of this array. More...
Public Member Functions inherited from PAbstractArray
	PAbstractArray (PINDEX elementSizeInBytes, PINDEX initialSize=0)
	Create a new dynamic array of initalSize elements of elementSizeInBytes bytes each. More...
	PAbstractArray (PINDEX elementSizeInBytes, const void *buffer, PINDEX bufferSizeInElements, PBoolean dynamicAllocation)
	Create a new dynamic array of bufferSizeInElements elements of elementSizeInBytes bytes each. More...
virtual void	PrintOn (ostream &strm) const
	Output the contents of the object to the stream. More...
virtual void	ReadFrom (istream &strm)
	Input the contents of the object from the stream. More...
virtual Comparison	Compare (const PObject &obj) const
	Get the relative rank of the two arrays. More...
void	Attach (const void *buffer, PINDEX bufferSize)
	Attach a pointer to a static block to the base array type. More...
void *	GetPointer (PINDEX minSize=1)
	Get a pointer to the internal array and assure that it is of at least the specified size. More...
const void *	GetPointer () const
virtual PINDEX	GetLength () const
	Retrun the length in bytes for the array. More...
PBoolean	Concatenate (const PAbstractArray &array)
	Concatenate one array to the end of this array. More...
Public Member Functions inherited from PContainer
	PContainer (PINDEX initialSize=0)
	Create a new unique container. More...
	PContainer (const PContainer &cont)
	Create a new refernce to container. More...
PContainer &	operator= (const PContainer &cont)
	Assign one container reference to another. More...
virtual	~PContainer ()
	Destroy the container class. More...
virtual PINDEX	GetSize () const
	Get the current size of the container. More...
__inline size_t	size () const
PBoolean	SetMinSize (PINDEX minSize)
	Set the minimum size of container. More...
virtual PBoolean	IsEmpty () const
	Determine if the container is empty. More...
__inline bool	empty () const
PBoolean	IsUnique () const
	Determine if container is unique reference. More...
virtual PBoolean	MakeUnique ()
	Make this instance to be the one and only reference to the container contents. More...
Public Member Functions inherited from PObject
__inline unsigned	GetTraceContextIdentifier () const
	Get PTRACE context identifier. More...
__inline void	SetTraceContextIdentifier (unsigned id)
__inline void	SetTraceContextIdentifier (const PObject &obj)
__inline void	SetTraceContextIdentifier (const PObject *obj)
__inline void	CopyTraceContextIdentifier (PObject &obj) const
__inline void	CopyTraceContextIdentifier (PObject *obj) const
virtual	~PObject ()
__inline const char *	GetClass () const
__inline bool	IsClass (const char *name) const
__inline const PObject *	PTraceObjectInstance () const
template<class CLS >
CLS *	CloneAs () const
	As for Clone() but converts to specified type. More...
virtual PINDEX	HashFunction () const
	This function yields a hash value required by the PDictionary class. More...
virtual Comparison	CompareObjectMemoryDirect (const PObject &obj) const
	Determine the byte wise comparison of two objects. More...
bool	operator== (const PObject &obj) const
	Compare the two objects. More...
bool	operator!= (const PObject &obj) const
	Compare the two objects. More...
bool	operator< (const PObject &obj) const
	Compare the two objects. More...
bool	operator> (const PObject &obj) const
	Compare the two objects. More...
bool	operator<= (const PObject &obj) const
	Compare the two objects. More...
bool	operator>= (const PObject &obj) const
	Compare the two objects. More...

Protected Member Functions
void	Reset ()
bool	Juxtapose (unsigned frequency1, unsigned frequency2, unsigned milliseconds, unsigned volume)
bool	Modulate (unsigned frequency, unsigned modulate, unsigned milliseconds, unsigned volume)
bool	PureTone (unsigned frequency, unsigned milliseconds, unsigned volume)
bool	Silence (unsigned milliseconds)
unsigned	CalcSamples (unsigned milliseconds, unsigned frequency1, unsigned frequency2=0)
void	AddSample (int sample, unsigned volume)
Protected Member Functions inherited from PScalarArray< T >
virtual void	ReadElementFrom (istream &stream, PINDEX index)
Protected Member Functions inherited from PBaseArray< T >
virtual void	PrintElementOn (ostream &stream, PINDEX index) const
	PBaseArray (PContainerReference &reference_)
Protected Member Functions inherited from PAbstractArray
PBoolean	InternalSetSize (PINDEX newSize, PBoolean force)
	PAbstractArray (PContainerReference &reference, PINDEX elementSizeInBytes)
Protected Member Functions inherited from PContainer
	PContainer (int dummy, const PContainer *cont)
	Constructor used in support of the Clone() function. More...
	PContainer (PContainerReference &reference)
	Construct using static PContainerReference. More...
virtual void	DestroyContents ()=0
	Destroy the container contents. More...
virtual void	AssignContents (const PContainer &c)
	Copy the container contents. More...
void	CopyContents (const PContainer &c)
	Copy the container contents. More...
void	CloneContents (const PContainer *src)
	Create a duplicate of the container contents. More...
void	Destruct ()
	Internal function called from container destructors. More...
virtual void	DestroyReference ()
	Destroy the PContainerReference instance. More...
Protected Member Functions inherited from PObject
	PObject ()
	Constructor for PObject, made protected so cannot ever create one on its own. More...

Protected Attributes
unsigned	m_sampleRate
unsigned	m_maxFrequency
unsigned	m_masterVolume
char	m_lastOperation
unsigned	m_lastFrequency1
unsigned	m_lastFrequency2
int	m_angle1
int	m_angle2
PINDEX	m_addPosition
Protected Attributes inherited from PAbstractArray
PINDEX	elementSize
	Size of an element in bytes. More...
char *	theArray
	Pointer to the allocated block of memory. More...
PBoolean	allocatedDynamically
	Flag indicating the array was allocated on the heap. More...
Protected Attributes inherited from PContainer
PContainerReference *	reference
Protected Attributes inherited from PObject
unsigned	m_traceContextIdentifier

Additional Inherited Members
Static Public Member Functions inherited from PObject
static __inline void	CopyTraceContextIdentifier (PObject &to, const PObject &from)
static __inline void	CopyTraceContextIdentifier (PObject &to, const PObject *from)
static __inline void	CopyTraceContextIdentifier (PObject *to, const PObject &from)
static __inline void	CopyTraceContextIdentifier (PObject *to, const PObject *from)
static __inline const char *	Class ()
static __inline const PObject *	PTraceObjectInstance (const char *)
static __inline const PObject *	PTraceObjectInstance (const PObject *obj)
template<typename T >
static Comparison	Compare2 (T v1, T v2)
	Compare two types, returning Comparison type. More...
static Comparison	InternalCompareObjectMemoryDirect (const PObject *obj1, const PObject *obj2, PINDEX size)
	Internal function caled from CompareObjectMemoryDirect() More...

Detailed Description

This class can be used to generate PCM data for tones (such as telephone calling tones and DTMF) at a sample rate of 8khz.

The class contains a master volume which is applied as well as the individual tone volumes. Thus a master volume ot 50% and a tone voluem of 50% would result in a net volume of 25%.

Tones may be described via a list of descriptor strings based on an ITU-T "semi-standard", one used within various standard documents but not a standard in itself. This format was enhanced to allow for multiple tones and volume indications.

The basic format is:

  [volume % ] frequency ':' cadence [ '/' ... ]

where frequency is one of frequency single frequency tone freq1 '+' freq2 two frequency juxtaposed (simple mixing) freq1 'x' freq2 first frequency modulated by second frequency freq1 '-' freq2 Alternate frequencies, generated tone is freq1 used for compatibility with tone filters Af0-G#9 Standard musical note codes, letters A to G followed by optional 'f' or '#' for flat or sharp, then on optional octave number from 0 to 9. A4 == 440Hz

and cadence is mintime ontime '-' offtime [ '-' ontime '-' offtime [ ... ] ]

and volume is a percentage of full volume

examples: 300:0.25 300Hz for minimum 250ms 1100:0.4-0.4 1100Hz with cadence 400ms on, 400ms off 900-1300:1.5 900Hz for 1.5 seconds 350+440:1 350Hz superimposed with 440Hz (US dial tone) for 1 second 425x15:0.4-0.2-0.4-2 425Hz modulated with 15Hz (Aus ring back tone) with cadence 400ms on, 200ms off, 400ms on, 2s off 425:0.4-0.1/50%425:0.4-0.1 425Hz with cadence 400ms on, 100ms off, 400ms on, 100ms off, where second tone is reduced in volume by 50%

A database of tones for all contries in the worls is available at: http://www.3amsystems.com/wireline/tone-search.htm

Member Enumeration Documentation

anonymous enum

Enumerator
MaxVolume
DefaultSampleRate
MinFrequency
MinModulation
SineScale

Constructor & Destructor Documentation

PTones::PTones	(	unsigned	masterVolume = MaxVolume,
		unsigned	sampleRate = DefaultSampleRate
	)

Create an empty tone buffer.

Tones added will use the specified master volume.

Parameters

masterVolume	Percentage volume
sampleRate	Sample rate of generated data

PTones::PTones	(	const PString &	descriptor,
		unsigned	masterVolume = MaxVolume,
		unsigned	sampleRate = DefaultSampleRate
	)

Create a filled tone buffer using the specified descriptor.

Parameters

descriptor	Descriptor string for tone(s). See class notes.
masterVolume	Percentage volume
sampleRate	Sample rate of generated data

Member Function Documentation

void PTones::AddSample ( int  sample, unsigned  volume  )

protected

unsigned PTones::CalcSamples ( unsigned  milliseconds, unsigned  frequency1, unsigned  frequency2 = 0  )

protected

bool PTones::Generate	(	const PString &	descriptor,
		unsigned	sampleRate = 0,
		unsigned	masterVolume = 0
	)

Generate a tone using the specified descriptor.

See class general notes for format of the descriptor string.

Parameters

descriptor	Descriptor string for tone(s). See class notes.
sampleRate	Sample rate of generated data
masterVolume	Percentage volume

Referenced by PDTMFEncoder::GenerateBusyTone(), PDTMFEncoder::GenerateDialTone(), and PDTMFEncoder::GenerateRingBackTone().

bool PTones::Generate	(	char	operation,
		unsigned	frequency1,
		unsigned	frequency2,
		unsigned	milliseconds,
		unsigned	volume = MaxVolume
	)

Generate a tone using the specified values.

The operation parameter may be '+', 'x', '-' or ' ' for summing, modulation, pure tone or silence resepctively. The tones duration is always rounded up to the nearest even multiple of the tone cycle to assure correct zero crossing when tones change.

Parameters

operation	Operation for mixing frequency
frequency1	Primary frequency for tone
frequency2	Secondary frequency for summing or modulation
milliseconds	Duration of tone
volume	Percentage volume

unsigned PTones::GetSampleRate ( ) const

inline

Get the sample rate for tones.

References m_sampleRate.

bool PTones::Juxtapose ( unsigned  frequency1, unsigned  frequency2, unsigned  milliseconds, unsigned  volume  )

protected

bool PTones::Modulate ( unsigned  frequency, unsigned  modulate, unsigned  milliseconds, unsigned  volume  )

protected

bool PTones::PureTone ( unsigned  frequency, unsigned  milliseconds, unsigned  volume  )

protected

void PTones::Reset ( )

protected

void PTones::SetSampleRate

(

unsigned

rate

)

Set sample rate for tones, note will clear tone buffer.

virtual PBoolean PTones::SetSize ( PINDEX  newSize )

virtual

Set the size of the array in elements.

A new array may be allocated to accomodate the new number of elements. If the array increases in size then the new bytes are initialised to zero. If the array is made smaller then the data beyond the new size is lost.

Returns

true if the memory for the array was allocated successfully.

Reimplemented from PAbstractArray.

bool PTones::Silence ( unsigned  milliseconds )

protected

bool PTones::Write ( PChannel &  channel )

inline

Write tones to channel.

References PAbstractArray::GetPointer(), PContainer::GetSize(), and PChannel::Write().

Member Data Documentation

PINDEX PTones::m_addPosition

protected

int PTones::m_angle1

protected

int PTones::m_angle2

protected

unsigned PTones::m_lastFrequency1

protected

unsigned PTones::m_lastFrequency2

protected

char PTones::m_lastOperation

protected

unsigned PTones::m_masterVolume

protected

unsigned PTones::m_maxFrequency

protected

unsigned PTones::m_sampleRate

protected

Referenced by GetSampleRate().

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

• dtmf.h