com.hissain.jscipy.signal.filter

Class Elliptic

java.lang.Object

com.hissain.jscipy.signal.filter.Elliptic

public class Elliptic
extends java.lang.Object

Elliptic (Cauer) Filter implementation. Provides static methods for filtering with elliptic filters. Elliptic filters offer the steepest rolloff for a given filter order by allowing ripple in both the passband and stopband.

Method Summary

Modifier and Type	Method and Description
static double[]	bandPass(double[] signal, double sampleRate, double centerFreq, double widthFreq, int order, double rippleDb, double stopBandDb, boolean zeroPhase) Applies a band-pass Elliptic filter.
static double[]	bandStop(double[] signal, double sampleRate, double centerFreq, double widthFreq, int order, double rippleDb, double stopBandDb, boolean zeroPhase) Applies a band-stop Elliptic filter.
static double[]	filter(double[] signal, double sampleRate, double cutoff, int order, double rippleDb, double stopBandDb) Applies a causal Elliptic low-pass filter (lfilter).
static double[]	filtfilt(double[] signal, double sampleRate, double cutoff, int order, double rippleDb, double stopBandDb) Applies a zero-phase Elliptic low-pass filter (filtfilt).
static double[]	highPass(double[] signal, double sampleRate, double cutoff, int order, double rippleDb, double stopBandDb, boolean zeroPhase) Applies a high-pass Elliptic filter.
static double[]	lowPass(double[] signal, double sampleRate, double cutoff, int order, double rippleDb, double stopBandDb, boolean zeroPhase) Applies a low-pass Elliptic filter.

Methods inherited from class java.lang.Object

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

Method Detail

lowPass

public static double[] lowPass(double[] signal,
                               double sampleRate,
                               double cutoff,
                               int order,
                               double rippleDb,
                               double stopBandDb,
                               boolean zeroPhase)

Applies a low-pass Elliptic filter.

Parameters:

signal - The input signal.

sampleRate - The sample rate.

cutoff - The cutoff frequency.

order - The filter order.

rippleDb - The passband ripple in decibels.

stopBandDb - The stopband attenuation in decibels.

zeroPhase - If true, applies zero-phase filtering (filtfilt); otherwise causal (lfilter).

Returns:

The filtered signal.

highPass

public static double[] highPass(double[] signal,
                                double sampleRate,
                                double cutoff,
                                int order,
                                double rippleDb,
                                double stopBandDb,
                                boolean zeroPhase)

Applies a high-pass Elliptic filter.

Parameters:

signal - The input signal.

sampleRate - The sample rate.

cutoff - The cutoff frequency.

order - The filter order.

rippleDb - The passband ripple in decibels.

stopBandDb - The stopband attenuation in decibels.

zeroPhase - If true, applies zero-phase filtering (filtfilt); otherwise causal (lfilter).

Returns:

The filtered signal.

bandPass

public static double[] bandPass(double[] signal,
                                double sampleRate,
                                double centerFreq,
                                double widthFreq,
                                int order,
                                double rippleDb,
                                double stopBandDb,
                                boolean zeroPhase)

Applies a band-pass Elliptic filter.

Parameters:

signal - The input signal.

sampleRate - The sample rate.

centerFreq - The center frequency.

widthFreq - The bandwidth.

order - The filter order.

rippleDb - The passband ripple in decibels.

stopBandDb - The stopband attenuation in decibels.

zeroPhase - If true, applies zero-phase filtering (filtfilt); otherwise causal (lfilter).

Returns:

The filtered signal.

bandStop

public static double[] bandStop(double[] signal,
                                double sampleRate,
                                double centerFreq,
                                double widthFreq,
                                int order,
                                double rippleDb,
                                double stopBandDb,
                                boolean zeroPhase)

Applies a band-stop Elliptic filter.

Parameters:

signal - The input signal.

sampleRate - The sample rate.

centerFreq - The center frequency.

widthFreq - The notch bandwidth.

order - The filter order.

rippleDb - The passband ripple in decibels.

stopBandDb - The stopband attenuation in decibels.

zeroPhase - If true, applies zero-phase filtering (filtfilt); otherwise causal (lfilter).

Returns:

The filtered signal.

filtfilt

public static double[] filtfilt(double[] signal,
                                double sampleRate,
                                double cutoff,
                                int order,
                                double rippleDb,
                                double stopBandDb)

Applies a zero-phase Elliptic low-pass filter (filtfilt).

Parameters:

signal - The input signal.

sampleRate - The sample rate.

cutoff - The cutoff frequency.

order - The filter order.

rippleDb - The passband ripple in decibels.

stopBandDb - The stopband attenuation in decibels.

Returns:

The filtered signal.

filter

public static double[] filter(double[] signal,
                              double sampleRate,
                              double cutoff,
                              int order,
                              double rippleDb,
                              double stopBandDb)

Applies a causal Elliptic low-pass filter (lfilter).

Parameters:

signal - The input signal.

sampleRate - The sample rate.

cutoff - The cutoff frequency.

order - The filter order.

rippleDb - The passband ripple in decibels.

stopBandDb - The stopband attenuation in decibels.

Returns:

The filtered signal.