var
 i: Integer;
 Src, Last, IIRLowPass, ComplementaryHighPass: Double;
begin
 Randomize;
 Last := 0;
 for i := -99 to 99 do begin
   Src := Pi/2 + ArcTan(i/10) + 0.5 * Random;
   IIRLowPass := Src * 0.2 + Last * 0.8;
   ComplementaryHighPass := Src - IIRLowPass;
   Series1.Add(Src);
   Series2.Add(IIRLowPass);
   Series3.Add(ComplementaryHighPass);
   Last := IIRLowPass;
 end;