public class ButterworthFilter extends RecursiveCascadeFilter
Modifier and Type | Class and Description |
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static class |
ButterworthFilter.Type
Filter type.
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Constructor and Description |
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ButterworthFilter(double fl,
double al,
double fh,
double ah)
Construct a Butterworth filter with specified parameters.
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ButterworthFilter(double fc,
int np,
ButterworthFilter.Type type)
Construct Butterworth filter with specified parameters.
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apply1Forward, apply1Forward, apply1ForwardReverse, apply1ForwardReverse, apply1Reverse, apply1Reverse, apply2Forward, apply2Forward, apply2ForwardReverse, apply2ForwardReverse, apply2Reverse, apply2Reverse, apply3Forward, apply3ForwardReverse, apply3Reverse, applyForward, applyForwardReverse, applyReverse, init
public ButterworthFilter(double fl, double al, double fh, double ah)
fl
- the low frequency at which the amplitude al is specified.
The low frequency fl must be greater than 0.0 and less than fh.al
- the amplitude at the specified low frequency fl.
The amplitude al must be greater than 0.0, less than 1.0, and
not equal to the amplitude ah.fh
- the high frequency at which the amplitude ah is is specified.
The high frequency fh must be less than 0.5 and greater than fl.ah
- the amplitude at the specified high frequency fh.
The amplitude ah must be greater than 0.0, less than 1.0, and
not equal to the amplitude al.public ButterworthFilter(double fc, int np, ButterworthFilter.Type type)
fc
- the cutoff (half-power) frequency, in cycles per sample.
At this cutuff frequency, the filter amplitude squared equals 0.5.
The cutoff frequency must be greater than 0.0 and less than 0.5.np
- the number of poles in the recursive filter.type
- the filter type.