com.jsyn.unitgen

Class FilterBiquad

java.lang.Object

com.jsyn.unitgen.UnitGenerator

com.jsyn.unitgen.UnitFilter

com.jsyn.unitgen.TunableFilter

com.jsyn.unitgen.FilterBiquad

All Implemented Interfaces:

UnitSink, UnitSource

Direct Known Subclasses:

FilterBiquadCommon, FilterBiquadShelf

public abstract class FilterBiquad
extends TunableFilter

Base class for a set of IIR filters.

See Also:

FilterBandStop, FilterBandPass, FilterLowPass, FilterHighPass, FilterTwoPoleTwoZero

Field Summary

Fields

Modifier and Type	Field and Description
UnitInputPort	amplitude

Fields inherited from class com.jsyn.unitgen.TunableFilter

frequency

Fields inherited from class com.jsyn.unitgen.UnitFilter

input, output

Fields inherited from class com.jsyn.unitgen.UnitGenerator

FALSE, TRUE

Constructor Summary

Constructors

Constructor and Description
FilterBiquad()

Method Summary

Methods

Modifier and Type	Method and Description
void	generate(int start, int limit) Generic generate(int start, int limit) method calls this filter's recalculate() and performBiquadFilter(int, int) methods.
void	performBiquadFilter(int start, int limit) Each filter calls performBiquadFilter() through the generate(int, int) method.

Methods inherited from class com.jsyn.unitgen.UnitFilter

getInput, getOutput

Methods inherited from class com.jsyn.unitgen.UnitGenerator

addPort, addPort, convertHalfLifeToMultiplier, flattenOutputs, generate, getCircuit, getFramePeriod, getFrameRate, getPortByName, getPorts, getSynthesisEngine, getSynthesizer, getTopUnit, getUnitGenerator, isEnabled, pullData, setCircuit, setEnabled, setFrameRate, setPort, setSynthesisEngine, start, start, stop, stop

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.jsyn.unitgen.UnitSink

getUnitGenerator, start, start, stop, stop

Methods inherited from interface com.jsyn.unitgen.UnitSource

getUnitGenerator

Field Detail

amplitude

public UnitInputPort amplitude

Constructor Detail

FilterBiquad

public FilterBiquad()

Method Detail

generate

public void generate(int start,
            int limit)

Generic generate(int start, int limit) method calls this filter's recalculate() and performBiquadFilter(int, int) methods.

Specified by:

generate in class UnitGenerator

Parameters:

start - offset into port buffers

limit - limit offset into port buffers for loop

performBiquadFilter

public void performBiquadFilter(int start,
                       int limit)

Each filter calls performBiquadFilter() through the generate(int, int) method. This method has converted Robert Bristow-Johnson's coefficients for the Direct I form in this way: Here is the equation that JSyn uses for this filter: y(n) = A0*x(n) + A1*x(n-1) + A2*x(n-2) - B1*y(n-1) - B2*y(n-2) Here is the equation that Robert Bristow-Johnson uses: y[n] = (b0/a0)*x[n] + (b1/a0)*x[n-1] + (b2/a0)*x[n-2] - (a1/a0)*y[n-1] - (a2/a0)*y[n-2] So to translate between JSyn coefficients and RBJ coefficients:

 JSyn => RBJ
 A0 => b0/a0
 A1 => b1/a0
 A2 => b2/a0
 B1 => a1/a0
 B2 => a2/a0
 

Parameters:

start -

limit -