jass.generators
Class Butter2LowFilter

java.lang.Object
  jass.generators.Butter2LowFilter

All Implemented Interfaces:

Filter

public class Butter2LowFilter
extends java.lang.Object
implements Filter

Second order Butterworth lowpass filter.

Author:

Kees van den Doel (kvdoel@cs.ubc.ca)

Field Summary

protected float	A Gain.
protected float	A0 Gain.
protected float	cc Coefficients (Steiglitz notation).
protected float	dd Coefficients (Steiglitz notation).
protected float	f Cutoff frequency in Hertz.
protected float	gain Gain.
protected float	srate Sampling rate in Hertz.

Constructor Summary

Butter2LowFilter(float srate)
Create and initialize.

Method Summary

void	filter(float[] output, float[] input, int nsamples, int inputOffset) Proces input (may be same as output).
void	reset() Reset state.
void	reset(float c) Reset state.
void	setCutoffFrequency(float f) Set the filter cutoff.
void	setGain(float gain) Set gain.

Methods inherited from class java.lang.Object

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

Field Detail

srate

protected float srate

Sampling rate in Hertz.

f

protected float f

Cutoff frequency in Hertz.

cc

protected float cc

Coefficients (Steiglitz notation).

dd

protected float dd

Coefficients (Steiglitz notation).

A

protected float A

Gain. A0 is normalized. A is actual gain, gain is user settable

A0

protected float A0

Gain. A0 is normalized. A is actual gain, gain is user settable

gain

protected float gain

Gain. A0 is normalized. A is actual gain, gain is user settable

Constructor Detail

Butter2LowFilter

public Butter2LowFilter(float srate)

Create and initialize.

Parameters:

srate - sampling rate in Hertz.

Method Detail

setCutoffFrequency

public void setCutoffFrequency(float f)

Set the filter cutoff.

Parameters:

f - cutoff frequency in Hertz.

setGain

public void setGain(float gain)

Set gain.

Parameters:

gain - gain.

reset

public void reset()

Reset state.

reset

public void reset(float c)

Reset state.

Parameters:

c - value of constant state

filter

public void filter(float[] output,
                   float[] input,
                   int nsamples,
                   int inputOffset)

Proces input (may be same as output).

Specified by:

filter in interface Filter

Parameters:

output - user provided buffer for returned result.

input - user provided input buffer.

nsamples - number of samples written to output buffer.

inputOffset - where to start in circular buffer input.