dsp::StateVariableTPTFilter< SampleType > Class Template Reference

An IIR filter that can perform low, band and high-pass filtering on an audio signal, with 12 dB of attenuation per octave, using a TPT structure, designed for fast modulation (see Vadim Zavalishin's documentation about TPT structures for more information). More...

#include <juce_StateVariableTPTFilter.h>

Public Types
using	Type = StateVariableTPTFilterType

Public Member Functions
	StateVariableTPTFilter ()
	Constructor.
void	setType (Type newType)
	Sets the filter type.
void	setCutoffFrequency (SampleType newFrequencyHz)
	Sets the cutoff frequency of the filter.
void	setResonance (SampleType newResonance)
	Sets the resonance of the filter.
Type	getType () const noexcept
	Returns the type of the filter.
SampleType	getCutoffFrequency () const noexcept
	Returns the cutoff frequency of the filter.
SampleType	getResonance () const noexcept
	Returns the resonance of the filter.
void	prepare (const ProcessSpec &spec)
	Initialises the filter.
void	reset ()
	Resets the internal state variables of the filter.
void	reset (SampleType newValue)
	Resets the internal state variables of the filter to a given value.
void	snapToZero () noexcept
	Ensure that the state variables are rounded to zero if the state variables are denormals.
template<typename ProcessContext >
void	process (const ProcessContext &context) noexcept
	Processes the input and output samples supplied in the processing context.
SampleType	processSample (int channel, SampleType inputValue)
	Processes one sample at a time on a given channel.

Detailed Description

template<typename SampleType>
class dsp::StateVariableTPTFilter< SampleType >

An IIR filter that can perform low, band and high-pass filtering on an audio signal, with 12 dB of attenuation per octave, using a TPT structure, designed for fast modulation (see Vadim Zavalishin's documentation about TPT structures for more information).

Its behaviour is based on the analog state variable filter circuit.

Note: The bandpass here is not the one in the RBJ CookBook as its gain can be higher than 0 dB. For the classic 0 dB bandpass, we need to multiply the result by R2.

Note 2: Using this class prevents some loud audio artefacts commonly encountered when changing the cutoff frequency using other filter simulation structures and IIR filter classes. However, this class may still require additional smoothing for cutoff frequency changes.

see IIRFilter, SmoothedValue

Member Typedef Documentation

Type

template<typename SampleType >

using dsp::StateVariableTPTFilter< SampleType >::Type = StateVariableTPTFilterType

Constructor & Destructor Documentation

StateVariableTPTFilter()

template<typename SampleType >

dsp::StateVariableTPTFilter< SampleType >::StateVariableTPTFilter

(

)

Constructor.

Member Function Documentation

setType()

template<typename SampleType >

void dsp::StateVariableTPTFilter< SampleType >::setType

(

Type

newType

)

Sets the filter type.

setCutoffFrequency()

template<typename SampleType >

void dsp::StateVariableTPTFilter< SampleType >::setCutoffFrequency

(

SampleType

newFrequencyHz

)

Sets the cutoff frequency of the filter.

Parameters

newFrequencyHz

the new cutoff frequency in Hz.

setResonance()

template<typename SampleType >

void dsp::StateVariableTPTFilter< SampleType >::setResonance

(

SampleType

newResonance

)

Sets the resonance of the filter.

Note: The bandwidth of the resonance increases with the value of the parameter. To have a standard 12 dB / octave filter, the value must be set at 1 / sqrt (2).

getType()

template<typename SampleType >

Type dsp::StateVariableTPTFilter< SampleType >::getType ( ) const

noexcept

Returns the type of the filter.

getCutoffFrequency()

template<typename SampleType >

SampleType dsp::StateVariableTPTFilter< SampleType >::getCutoffFrequency ( ) const

noexcept

Returns the cutoff frequency of the filter.

getResonance()

template<typename SampleType >

SampleType dsp::StateVariableTPTFilter< SampleType >::getResonance ( ) const

noexcept

Returns the resonance of the filter.

prepare()

template<typename SampleType >

void dsp::StateVariableTPTFilter< SampleType >::prepare

(

const ProcessSpec &

spec

)

Initialises the filter.

reset() [1/2]

template<typename SampleType >

void dsp::StateVariableTPTFilter< SampleType >::reset

(

)

Resets the internal state variables of the filter.

reset() [2/2]

template<typename SampleType >

void dsp::StateVariableTPTFilter< SampleType >::reset

(

SampleType

newValue

)

Resets the internal state variables of the filter to a given value.

snapToZero()

template<typename SampleType >

void dsp::StateVariableTPTFilter< SampleType >::snapToZero ( )

noexcept

Ensure that the state variables are rounded to zero if the state variables are denormals.

This is only needed if you are doing sample by sample processing.

Referenced by dsp::StateVariableTPTFilter< SampleType >::process().

process()

template<typename SampleType >

template<typename ProcessContext >

void dsp::StateVariableTPTFilter< SampleType >::process ( const ProcessContext & context )

noexcept

Processes the input and output samples supplied in the processing context.

References jassert, dsp::StateVariableTPTFilter< SampleType >::processSample(), and dsp::StateVariableTPTFilter< SampleType >::snapToZero().

processSample()

template<typename SampleType >

SampleType dsp::StateVariableTPTFilter< SampleType >::processSample	(	int	channel,
		SampleType	inputValue )

Processes one sample at a time on a given channel.

Referenced by dsp::StateVariableTPTFilter< SampleType >::process().

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

• juce_StateVariableTPTFilter.h