void KaiserImpulse(TVec H, Double[] W, Double Ripple, TFilterType FilterType, Double Gain, Double FS, Boolean EnsuredOdd)
Design a FIR filter with a Kaiser window.
| # | Name | Type | Description |
|---|---|---|---|
| 1 | H | TVec | source TVec |
| 2 | W | Double[] | |
| 3 | Ripple | Double | scalar |
| 4 | FilterType | TFilterType | |
| 5 | Gain | Double | scalar |
| 6 | FS | Double | scalar |
| 7 | EnsuredOdd | Boolean |
Result: stored in self (calling object)
Remarks:
Compute a FIR impulse response filter with kaiser window applied and place the result in H. The transition regions are defined with the W array. There must be at least one (lowpass, highpass) and at most two (bandpass, bandstop) transition regions (2 or 4 elements). Filter type is defined with TFilterType.
FS is the sampling frequency. The length of the filter (H.Length) is based on the narrowest transition region in combination with the passband Ripple parameter. 20*Log10(Ripple) is also the required attenuation of the stopband in decibel. Gain defines the filter gain. The resulting H vector contains FIR type impulse response, which can be passed to the FirInit routine.
If EnsuredOdd is True, the filter length is guaranteed to have odd length. H.FloatPrecision value on input defines the precision (single or double) of the result on output.
Examples
using Dew.Math;
using Dew.Math.Editors;
using Dew.Math.Units;
using Dew.Signal;
using Dew.Signal.Units;
using Dew.Math.Tee;
using Dew.Signal.Tee;
private void button1_Click(object sender, EventArgs e)
{
Vector h = new Vector(0);
Vector response = new Vector(0);
Vector x;
double FS = 2; //sampling frequency
double Ripple = 0.001; // 60 dB stopband and 0.001 ripple in the passband
// Lowpass design with transition band between 0.3 and 0.5 Hz.
SignalUtils.KaiserImpulse(h, new double[2] {0.3,0.5} , Ripple, TFilterType.ftLowpass,1,FS,true);
SignalUtils.FrequencyResponse(h, null, response,8,false, TSignalWindowType.wtRectangular,0);
x = MtxExpr.Ramp(response.Length, TMtxFloatPrecision.mvDouble, 0,1.0/response.Length);
MtxVecTee.DrawIt(x, response,"Lowpass design with transition band between 0.3 and 0.5 Hz",false);
// Highpass design with transition band between 0.3 and 0.5 Hz.
SignalUtils.KaiserImpulse(h, new double[2] {0.3,0.5} , Ripple,TFilterType.ftHighpass,1,FS,true);
SignalUtils.FrequencyResponse(h, null, response,8,false, TSignalWindowType.wtRectangular,0);
MtxVecTee.DrawIt(x, response,"Highpass design with transition band between 0.3 and 0.5 Hz",false);
// Bandpass design with transition bands between 0.3..0.4 Hz and between 0.5...06 Hz.
SignalUtils.KaiserImpulse(h, new double[4] {0.3,0.4,0.5,0.6} , Ripple,TFilterType.ftBandpass,1,FS,true);
SignalUtils.FrequencyResponse(h, null, response,8, false,TSignalWindowType.wtRectangular,0);
x = MtxExpr.Ramp(response.Length, TMtxFloatPrecision.mvDouble,0,1.0/response.Length);
MtxVecTee.DrawIt(x, response,"Bandpass with transition bands 0.3-0.4 Hz and 0.5-0.6 Hz.",false);
// Bandstop design with transition bands between 0.3..0.4 Hz and between 0.5...06 Hz.
SignalUtils.KaiserImpulse(h, new double[4] {0.3,0.4,0.5,0.6} , Ripple,TFilterType.ftBandstop,1,FS,false);
SignalUtils.FrequencyResponse(h, null, response,8, false, TSignalWindowType.wtRectangular,0);
x = MtxExpr.Ramp(response.Length, TMtxFloatPrecision.mvDouble,0,1.0/response.Length);
MtxVecTee.DrawIt(x, response,"Bandstop with transition bands 0.3-0.4 Hz and 0.5-0.6 Hz.",false);
//Hilbert III with transition bands between 0.0-0.1 Hz and 0.9-1.0 Hz.
SignalUtils.KaiserImpulse(h, new double[2] {0.9,1} , Ripple,TFilterType.ftHilbertIII,1,FS,false);
SignalUtils.FrequencyResponse(h, null, response,8, false, TSignalWindowType.wtRectangular,0);
x = MtxExpr.Ramp(response.Length, TMtxFloatPrecision.mvDouble,0,1.0/response.Length);
MtxVecTee.DrawIt(x, response,"Hilbert III with transition bands between 0.0-0.1 Hz and 0.9-1.0 Hz.",false);
//Hilbert IV with transition band between 0.0-0.1 Hz.
SignalUtils.KaiserImpulse(h, new double[2] {0.9,1} , Ripple,TFilterType.ftHilbertIV,1,FS,false);
SignalUtils.FrequencyResponse(h, null, response,8, false, TSignalWindowType.wtRectangular,0);
x = MtxExpr.Ramp(response.Length, TMtxFloatPrecision.mvDouble,0,1.0/response.Length);
MtxVecTee.DrawIt(x, response,"Hilbert IV with transition band between 0.0-0.1 Hz",false);
//Differentiator III with transition band between 0.0-0.1 and 0.9-1.0 Hz.
SignalUtils.KaiserImpulse(h, new double[2] {0.9,1} , Ripple,TFilterType.ftDifferentiatorIII,1,FS,false);
SignalUtils.FrequencyResponse(h, null, response,8, false, TSignalWindowType.wtRectangular,0);
x = MtxExpr.Ramp(response.Length, TMtxFloatPrecision.mvDouble,0,1.0/response.Length);
MtxVecTee.DrawIt(x, response,"Differentiator III with transitions between 0.0-0.1 and 0.9-1.0 Hz",false);
//Differentiator IV with transition band between 0.0 and 0.1 Hz.
SignalUtils.KaiserImpulse(h, new double[2] {0.9,1} , Ripple,TFilterType.ftDifferentiatorIV,1,FS,false);
SignalUtils.FrequencyResponse(h, null, response,8, false, TSignalWindowType.wtRectangular,0);
x = MtxExpr.Ramp(response.Length, TMtxFloatPrecision.mvDouble,0,1.0/response.Length);
MtxVecTee.DrawIt(x, response,"Differentiator IV with transitions between 0.0-0.1 Hz",false);
}