ddf.minim.effects
Class LowPassFS
java.lang.Object
ddf.minim.effects.IIRFilter
ddf.minim.effects.LowPassFS
- All Implemented Interfaces:
- AudioEffect
public class LowPassFS
- extends IIRFilter
LowPassFS is a four stage low pass filter. It becomes unstable if the cutoff
frequency is set below 60 Hz, so it will report and error and set the cutoff
to 60 Hz if you try to set it lower.
- Author:
- Damien Di Fede
Fields inherited from class ddf.minim.effects.IIRFilter |
a, b |
Constructor Summary |
LowPassFS(float freq,
float sampleRate)
Constructs a low pass filter with a cutoff frequency of freq
that will be used to filter audio recorded at sampleRate . |
Method Summary |
protected void |
calcCoeff()
Calculates the coefficients of the filter using the current cutoff
frequency. |
boolean |
validFreq(float f)
Returns true if the frequency is valid for this filter. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
LowPassFS
public LowPassFS(float freq,
float sampleRate)
- Constructs a low pass filter with a cutoff frequency of
freq
that will be used to filter audio recorded at sampleRate
.
- Parameters:
freq
- the cutoff frequencysampleRate
- the sample rate of the audio that will be filtered
validFreq
public boolean validFreq(float f)
- Description copied from class:
IIRFilter
- Returns true if the frequency is valid for this filter. Subclasses can
override this method if they want to limit center frequencies to certain
ranges to avoid becoming unstable. The default implementation simply
makes sure that
f
is positive.
- Overrides:
validFreq
in class IIRFilter
- Parameters:
f
- the frequency (in Hz) to validate
- Returns:
- true if
f
is a valid frequency for this filter
calcCoeff
protected void calcCoeff()
- Description copied from class:
IIRFilter
- Calculates the coefficients of the filter using the current cutoff
frequency. To make your own IIRFilters, you must extend IIRFilter and
implement this function. The frequency is expressed as a fraction of the
sample rate. When filling the coefficient arrays, be aware that
b[0]
corresponds to the coefficient b1
.
- Specified by:
calcCoeff
in class IIRFilter