procedure IDFT (pREAL,pIMAG:ZISU;  n:integer; var VALREAL,VALIMAG:ZISU );
 type ZISU= array[0..99] of real;
  var a,b            : integer;
      ARG            : ZISU;
      OMEGAc,OMEGAs  : real;
    begin
       for a:=0 to n-1 do
          ARG[a]:=(2*3.14*a*(-1))/n;
       for a:=0 to n-1 do
          begin
             VALREAL[a]:=0;
             VALIMAG[a]:=0;
             for b:=0 to n-1 do
                begin
                   OMEGAc:=cos(ARG[a]*b);
                   OMEGAs:=sin(ARG[a]*b);
                   VALREAL[a]:=VALREAL[a]+pREAL[b]*OMEGAc-pIMAG[b]*OMEGAs;
                   VALIMAG[a]:=VALIMAG[a]+pREAL[b]*OMEGAs+pIMAG[b]*OMEGAc
                end;
            VALREAL[a]:=VALREAL[a]/n;
            VALIMAG[a]:=VALIMAG[a]/n
         end
    end;