LowPassFilter Class Reference

A resonant low pass filter for audio signals. More...

#include <LowPassFilter.h>

Public Member Functions
	LowPassFilter ()
	Constructor.
void	setCutoffFreq (uint8_t cutoff)
	deprecated. More...
void	setResonance (uint8_t resonance)
	deprecated. More...
void	setCutoffFreqAndResonance (uint8_t cutoff, uint8_t resonance)
	Set the cut off frequency and resonance. More...
int	next (int in)
	Calculate the next sample, given an input signal. More...

Detailed Description

A resonant low pass filter for audio signals.

Definition at line 38 of file LowPassFilter.h.

Member Function Documentation

next()

int LowPassFilter::next ( int  in )

inline

Calculate the next sample, given an input signal.

Parameters

in	the signal input.

Returns

the signal output.

Note

Timing: about 11us.

Definition at line 90 of file LowPassFilter.h.

setCutoffFreq()

void LowPassFilter::setCutoffFreq ( uint8_t  cutoff )

inline

deprecated.

Use setCutoffFreqAndResonance(uint8_t cutoff, uint8_t resonance).

Set the cut off frequency,

Parameters

cutoff

use the range 0-255 to represent 0-8191 Hz (AUDIO_RATE/2). Be careful of distortion at the lower end, especially with high resonance.

Definition at line 53 of file LowPassFilter.h.

setCutoffFreqAndResonance()

void LowPassFilter::setCutoffFreqAndResonance ( uint8_t  cutoff, uint8_t  resonance  )

inline

Set the cut off frequency and resonance.

Replaces setCutoffFreq() and setResonance(). (Because the internal calculations need to be done whenever either parameter changes.)

Parameters

cutoff	range 0-255 represents 0-8191 Hz (AUDIO_RATE/2). Be careful of distortion at the lower end, especially with high resonance.
resonance	range 0-255, 255 is most resonant.

Definition at line 76 of file LowPassFilter.h.

setResonance()

void LowPassFilter::setResonance ( uint8_t  resonance )

inline

deprecated.

Use setCutoffFreqAndResonance(uint8_t cutoff, uint8_t resonance).

Set the resonance. If you hear unwanted distortion, back off the resonance. After setting resonance, you need to call setCuttoffFreq() to hear the change!

Parameters

resonance

in the range 0-255, with 255 being most resonant.

Note

Remember to call setCuttoffFreq() after resonance is changed!

Definition at line 67 of file LowPassFilter.h.