You are here: Symbol Reference > IIRFilters Namespace > Functions > IIRFilters.ChebyshevIIFilter Function
DSP Master VCL
ContentsIndex
PreviousUpNext
IIRFilters.ChebyshevIIFilter Function
IIrFilters | Functions | Example | See Also
Collapse All

The resulting transfer function is returned in the state-space form with A,B,C,D variables.

Pascal
function ChebyshevIIFilter(Order: integer; StopRipple: double; const CutoffFreq: array of double; FilterType: TFilterType; Analog: boolean; const A: TMtx; const B: TVec; const C: TVec; out d: double): double; overload;
File
See Also
Example

Design a discrete highpass filter with transition band between 10..12 Hz, if the sampling frequency is 30 Hz. The stopband should have more then 50 dB attenuation and the passband should not have more then 0.2dB ripple.  

This example does not actually filter data. It only designs the filter. To see how to actually apply the filter check the IirInit and IirInitBQ routines. 

 

  uses MtxExpr, Math387, MtxVec, SignalUtils, MtxVecTee, MtxVecEdit, IirFilters,
       LinearSystems;

  procedure TForm1.Button1Click(Sender: TObject);
  var z,p, num,den, FreqFr,Response: Vector;
      Order: integer;
      k,Bw,Wc: double;
      WcArray: TDoubleArray; //modified 3dB frequency
  begin
      SetLength(WcArray,1);
      Order := ChebyshevIIOrder([10*2/30,12*2/30],0.2,50,ftHighpass,WcArray,false);
      ChebyshevIIFilter(Order,50,WcArray,ftHighpass,false,num,den);
      FrequencyResponse(num,den,Response,64);
      FreqFr := Ramp(Response.Length,mvDouble,0,1.0/Response.Length); //X axis
      DrawIt(FreqFr,20*Log10(Abs(Response)));
  end;

 

  #include "MtxExpr.hpp"
  #include "MtxVecEdit.hpp"
  #include "MtxVecTee.hpp"
  #include "SignalUtils.hpp"
  #include "IirFilters.hpp"
  #include "LinearSystems.hpp"

  void __fastcall TForm41::BitBtn1Click(TObject *Sender)
  {
    sVector z,p, num, den, FreqFr, Response, WcArray;
    int   Order;
    double k,Wc,Bw;

    WcArray.Size(1);
    Order = ChebyshevIIOrder(OPENARRAY(double,(10.0*2/30,12.0*2/30)),0.2,50,ftHighpass,WcArray.PValues1D(0),WcArray.Length-1,false);
    ChebyshevIIFilter(Order,50,WcArray.PValues1D(0),WcArray.Length-1,ftHighpass,false,num,den);
    FrequencyResponse(num,den,Response,64);
    FreqFr = Ramp(Response.Length,mvDouble,0,1.0/Response.Length); //X axis
    DrawIt(FreqFr,20*Log10(Abs(Response)),"Frequency response",false);
  }
Group
Links
Copyright (c) 1999-2025 by Dew Research. All rights reserved.
What do you think about this topic? Send feedback!