public class IirFilterDesignFisher extends Object
This class is based on a Java port of C source code by Anthony J. Fisher.
|Modifier and Type||Method and Description|
Designs an IIR filter and returns the IIR filter coefficients.
public static IirFilterCoefficients design(FilterPassType filterPassType, FilterCharacteristicsType filterCharacteristicsType, int filterOrder, double ripple, double fcf1, double fcf2)
The cutoff frequencies are specified relative to the sampling rate and must be
between 0 and 0.5.
The following formula can be used to calculate the relative frequency values:
frequencyInHz / samplingRateInHz
For Bessel filters, matched Z-transform is used to design the filter.
filterPassType- The filter pass type (Lowpass, highpass, bandpass, bandstop).
filterCharacteristicsType- The filter characteristics type. The following filters are implemented: Butterworth, Chebyshev (type 1), Bessel.
filterOrder- The filter order.
ripple- Passband ripple in dB. Must be negative. Only used for Chebyshev filter, ignored for other filters.
fcf1- The relative filter cutoff frequency for lowpass/highpass, lower cutoff frequency for bandpass/bandstop. This value is relative to the sampling rate (see above for more details).
fcf2- Ignored for lowpass/highpass, the relative upper cutoff frequency for bandpass/bandstop, This value is relative to the sampling rate (see above for more details).