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STK two-pole filter class. More...
#include <TwoPole.h>
Public Member Functions | |
TwoPole (void) | |
Default constructor creates a second-order pass-through filter. | |
~TwoPole () | |
Class destructor. | |
void | ignoreSampleRateChange (bool ignore=true) |
A function to enable/disable the automatic updating of class data when the STK sample rate changes. | |
void | setB0 (StkFloat b0) |
Set the b[0] coefficient value. | |
void | setA1 (StkFloat a1) |
Set the a[1] coefficient value. | |
void | setA2 (StkFloat a2) |
Set the a[2] coefficient value. | |
void | setCoefficients (StkFloat b0, StkFloat a1, StkFloat a2, bool clearState=false) |
Set all filter coefficients. | |
void | setResonance (StkFloat frequency, StkFloat radius, bool normalize=false) |
Sets the filter coefficients for a resonance at frequency (in Hz). | |
StkFloat | lastOut (void) const |
Return the last computed output value. | |
StkFloat | tick (StkFloat input) |
Input one sample to the filter and return one output. | |
StkFrames & | tick (StkFrames &frames, unsigned int channel=0) |
Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs. | |
StkFrames & | tick (StkFrames &iFrames, StkFrames &oFrames, unsigned int iChannel=0, unsigned int oChannel=0) |
Take a channel of the iFrames object as inputs to the filter and write outputs to the oFrames object. |
STK two-pole filter class.
This class implements a two-pole digital filter. A method is provided for creating a resonance in the frequency response while maintaining a nearly constant filter gain.
by Perry R. Cook and Gary P. Scavone, 1995 - 2010.
void stk::TwoPole::setResonance | ( | StkFloat | frequency, | |
StkFloat | radius, | |||
bool | normalize = false | |||
) |
Sets the filter coefficients for a resonance at frequency (in Hz).
This method determines the filter coefficients corresponding to two complex-conjugate poles with the given frequency (in Hz) and radius from the z-plane origin. If normalize is true, the coefficients are then normalized to produce unity gain at frequency (the actual maximum filter gain tends to be slightly greater than unity when radius is not close to one). The resulting filter frequency response has a resonance at the given frequency. The closer the poles are to the unit-circle (radius close to one), the narrower the resulting resonance width. An unstable filter will result for radius >= 1.0. For a better resonance filter, use a BiQuad filter.
Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
The StkFrames argument reference is returned. The channel
argument must be less than the number of channels in the StkFrames argument (the first channel is specified by 0). However, range checking is only performed if _STK_DEBUG_ is defined during compilation, in which case an out-of-range value will trigger an StkError exception.
Implements stk::Filter.
StkFrames & stk::TwoPole::tick | ( | StkFrames & | iFrames, | |
StkFrames & | oFrames, | |||
unsigned int | iChannel = 0 , |
|||
unsigned int | oChannel = 0 | |||
) | [inline] |
Take a channel of the iFrames
object as inputs to the filter and write outputs to the oFrames
object.
The iFrames
object reference is returned. Each channel argument must be less than the number of channels in the corresponding StkFrames argument (the first channel is specified by 0). However, range checking is only performed if _STK_DEBUG_ is defined during compilation, in which case an out-of-range value will trigger an StkError exception.
The Synthesis ToolKit in C++ (STK) |
©1995-2010 Perry R. Cook and Gary P. Scavone. All Rights Reserved. |