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TwoZero Class Reference

#include <TwoZero.h>

Inheritance diagram for TwoZero:

Filter Stk List of all members.

Detailed Description

STK two-zero filter class.

This protected Filter subclass implements a two-zero digital filter. A method is provided for creating a "notch" in the frequency response while maintaining a constant filter gain.

by Perry R. Cook and Gary P. Scavone, 1995 - 2007.


Public Member Functions

 TwoZero ()
 Default constructor creates a second-order pass-through filter.
 ~TwoZero ()
 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 the 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 setNotch (StkFloat frequency, StkFloat radius)
 Sets the filter coefficients for a "notch" at frequency (in Hz).
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.
StkFloat tick (StkFloat sample)
 Input one sample to the filter and return one output.
StkFramestick (StkFrames &frames, unsigned int channel=0)
 Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.


Member Function Documentation

void TwoZero::setNotch StkFloat  frequency,
StkFloat  radius
 

Sets 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. The coefficients are then normalized to produce a maximum filter gain of one (independent of the filter gain parameter). The resulting filter frequency response has a "notch" or anti-resonance at the given frequency. The closer the zeros are to the unit-circle (radius close to or equal to one), the narrower the resulting notch width.

void TwoZero::setGain StkFloat  gain  )  [virtual]
 

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.

StkFrames& TwoZero::tick StkFrames frames,
unsigned int  channel = 0
[virtual]
 

Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.

The channel argument should be zero or greater (the first channel is specified by 0). An StkError will be thrown if the channel argument is equal to or greater than the number of channels in the StkFrames object.

Reimplemented from Filter.


The documentation for this class was generated from the following file:
The Synthesis ToolKit in C++ (STK)
©1995-2007 Perry R. Cook and Gary P. Scavone. All Rights Reserved.