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#include <BiQuad.h>
Inheritance diagram for BiQuad:
This protected Filter subclass implements a two-pole, two-zero digital filter. A method is provided for creating a resonance in the frequency response while maintaining a constant filter gain.
by Perry R. Cook and Gary P. Scavone, 1995 - 2007.
Public Member Functions | |
BiQuad () | |
Default constructor creates a second-order pass-through filter. | |
virtual | ~BiQuad () |
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 | clear (void) |
Clears all internal states of the filter. | |
void | setB0 (StkFloat b0) |
Set the b[0] coefficient value. | |
void | setB1 (StkFloat b1) |
Set the b[1] coefficient value. | |
void | setB2 (StkFloat b2) |
Set the b[2] coefficient value. | |
void | setA1 (StkFloat a1) |
Set the a[1] coefficient value. | |
void | setA2 (StkFloat a2) |
Set the a[2] coefficient value. | |
void | setResonance (StkFloat frequency, StkFloat radius, bool normalize=false) |
Sets the filter coefficients for a resonance at frequency (in Hz). | |
void | setNotch (StkFloat frequency, StkFloat radius) |
Set the filter coefficients for a notch at frequency (in Hz). | |
void | setEqualGainZeroes () |
Sets the filter zeroes for equal resonance gain. | |
void | setGain (StkFloat gain) |
Set the filter gain. | |
StkFloat | getGain (void) const |
Return the current filter gain. | |
StkFloat | lastOut (void) const |
Return the last computed output value. | |
virtual StkFloat | tick (StkFloat sample) |
Input one sample to the filter and return one output. | |
virtual 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. |
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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 filter zeros are placed at z = 1, z = -1, and the coefficients are then normalized to produce a constant unity peak gain (independent of the filter gain parameter). 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. |
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Set the filter coefficients for a notch at frequency (in Hz). This method determines the filter coefficients corresponding to two complex-conjugate zeros with the given frequency (in Hz) and radius from the z-plane origin. No filter normalization is attempted. |
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Sets the filter zeroes for equal resonance gain. When using the filter as a resonator, zeroes places at z = 1, z = -1 will result in a constant gain at resonance of 1 / (1 - R), where R is the pole radius setting. |
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Set the filter gain. The gain is applied at the filter input and does not affect the coefficient values. The default gain value is 1.0. Reimplemented from Filter. |
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Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
The Reimplemented from Filter. |
The Synthesis ToolKit in C++ (STK) |
©1995-2007 Perry R. Cook and Gary P. Scavone. All Rights Reserved. |