Comb< Tv, Si, Tp, Ts > Class Template Reference

Variable length delay-line with feedback and/or feedforward. More...

#include <Delay.h>

Inheritance diagram for Comb< Tv, Si, Tp, Ts >:

List of all members.

Public Member Functions
	Comb ()
	Default constructor. Does not allocate memory.
	Comb (float delay, const Tp &ffd=Tp(0), const Tp &fbk=Tp(0))
	Comb (float maxDelay, float delay, const Tp &ffd, const Tp &fbk)
void	decay (float units, float end=0.001f)
	Set number of units for response to decay to end value.
void	allPass (const Tp &v)
	Sets feedback to argument and feedforward to argument negated.
void	fbk (const Tp &v)
	Set feedback amount, in (-1, 1)
void	ffd (const Tp &v)
	Set feedforward amount [-1, 1].
void	set (float delay, const Tp &ffd, const Tp &fbk)
	Set several parameters.
Tv	operator() (const Tv &i0)
	Returns next filtered value.
Tv	operator() (const Tv &i0, const Tv &oN)
	Circulate filter with ffd & fbk.
Tv	circulateFbk (const Tv &i0, const Tv &oN)
	Circulate filter with fbk only.
Tv	nextFbk (const Tv &i0)
	Filters sample (feedback only).
float	norm () const
	Get unity gain scale factor.
float	normFbk () const
	Get unity gain scale factor due to feedback.
float	normFfd () const
	Get unity gain scale factor due to feedforward.
Tp	ffd () const
	Get feedforward amount.
Tp	fbk () const
	Get feedback amount.
void	delay (float v)
	Set delay length.
float	delay () const
	Get current delay length.
void	delayUnit (float u)
	Set delay as (0, 1) of buffer size.
float	delayUnit () const
	Get unit delay (to max delay)
void	freq (float v)
	Set natural frequency (1/delay())
float	freq () const
	Get frequency of delay line.
void	ipolType (ipl::Type v)
	Set interpolation type.
void	maxDelay (float v)
	Set maximum delay length.
float	maxDelay () const
	Get maximum delay length units.
void	zero ()
	Sets all elements to zero.
Tv	operator() () const
	Reads delayed element from buffer.
Tv	read (float ago)
	Returns element 'ago' units ago.
void	write (const Tv &v)
	Writes element into buffer. Tap is post-incremented.
void	writePre (const Tv &v)
	Writes element into buffer. Tap is pre-incremented.
uint32_t	delayIndex (uint32_t delay) const
	Get index of delayed element.
uint32_t	indexBack () const
	Get index of backmost element.
uint32_t	fracBits () const
	Returns number of bits in fraction (32 - bits())
float	fraction (uint32_t phase) const
	Get floating-point fractional part of fixed-point phase.
uint32_t	index (uint32_t phase) const
	Get integer part of fixed-point phase.
uint32_t	log2Size () const
	Returns log base-2 of the number of array elements.
uint32_t	oneIndex () const
	Returns 32-bit phase increment for one element index.
const Tv &	atPhase (uint32_t phase) const
	Get element at truncated fixed-point phase.
void	putPhase (uint32_t phase, Tvv)
	Set element at truncated fixed point phase.
Tv &	operator[] (uint32_t i)
	Get write reference to element.
const Tv &	operator[] (uint32_t i) const
	Get read-only reference to element.
ArrayBase &	assign (const Tv &v)
	Sets all elements to value.
ArrayBase &	assign (const Tv &v, uint32_t end, uint32_t stride=1, uint32_t start=0)
	Sets linear slice of elements to value.
Tv *	elems ()
	Get writable pointer to elements.
const Tv *	elems () const
	Get read-only pointer to elements.
uint32_t	size () const
	Returns number of elements in array.
void	clear ()
	Destroys all elements and frees memory.
void	own ()
	Ensures ownership of elements.
bool	isSoleOwner () const
	Returns true if we are the sole owner of data internally allocated.
void	resize (uint32_t newSize, const Tv &c=Tv())
	Resizes number of elements in array.
void	source (ArrayBase< Tv, SizeArrayPow2, gam::Allocator< Tv > > &src)
	Sets source of array elements to another array.
void	source (Tv *src, uint32_t size)
	Sets source of array elements to another array.
Static Public Member Functions
static int	references (Tv *m)
	Returns number of pointers to memory address being managed.

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Detailed Description

template<class Tv = gam::real, template< class > class Si = ipl::Linear, class Tp = gam::real, class Ts = Synced>
class gam::Comb< Tv, Si, Tp, Ts >

Variable length delay-line with feedback and/or feedforward.

The general comb filter transfer function provides N evenly spaced poles and/or zeroes around the unit circle. Feedback and feedforward produce evenly spaced resonances and notches, respectively, in the frequency response. Positive feeds result in even harmonics and negative feeds give odd harmonics. If the feedback and feedforward amounts are inverses of each other, an Nth order all-pass filter results. Comb filters are stable as long as |feedback| < 1.

Template Parameters:

Tv	value type
Si	interpolation strategy
Tp	parameter type
Ts	sync type

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Constructor & Destructor Documentation

Comb	(	float	delay,
		const Tp &	ffd = Tp(0),
		const Tp &	fbk = Tp(0)
	)

Parameters:

[in]	delay	Delay length. The size of the delay line will be the smallest possible power of two.
[in]	ffd	Feedforward amount, in [-1, 1]
[in]	fbk	Feedback amount, in (-1, 1)

Comb	(	float	maxDelay,
		float	delay,
		const Tp &	ffd,
		const Tp &	fbk
	)

Parameters:

[in]	maxDelay	Maximum delay length. The size of the delay line will be the smallest possible power of two.
[in]	delay	Delay length
[in]	ffd	Feedforward amount, in [-1, 1]
[in]	fbk	Feedback amount, in (-1, 1)

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Member Function Documentation

ArrayBase& assign	(	const Tv &	v,
		uint32_t	end,
		uint32_t	stride = 1,
		uint32_t	start = 0
	)		[inherited]

Sets linear slice of elements to value.

Parameters:

[in]	v	value to be copied as new content
[in]	end	end index (exclusive)
[in]	stride	index stride amount
[in]	start	start index (inclusive)

void decay	(	float	units,
		float	end = 0.001f
	)

Set number of units for response to decay to end value.

The sign of the decay length determines the sign of the feedback coefficient. The default end value of 0.001 (-60 dB) is the reverberation time of the filter. Setting the decay amount effects only the feedback value. The decay must be updated whenever the delay length of the filter changes.

void own

(

)

[inherited]

Ensures ownership of elements.

If the array is not already the sole owner, new memory is allocated and the previously referenced array elements are copied.

void resize	(	uint32_t	newSize,
		const Tv &	c = T()
	)		[inherited]

Resizes number of elements in array.

If the new size is less than the old size, then elements are truncated. If the new size is greater than the old size, then the argument value is copied into the additional elements.

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

• /Users/ljp/code/gamma/trunk/Gamma/Delay.h