| | | Scilab Reference Manual | |
|---|
fsfirlin — design of FIR, linear phase filters, frequency sampling technique
[hst]=fsfirlin(hd,flag)
| hd | : vector of desired frequency response samples |
| flag | : is equal to 1 or 2, according to the choice of type 1 or type 2 design |
| hst | : vector giving the approximated continuous response on a dense grid of frequencies |
function for the design of FIR, linear phase filters using the frequency sampling technique
// //Example of how to use the fsfirlin macro for the design //of an FIR filter by a frequency sampling technique. // //Two filters are designed : the first (response hst1) with //abrupt transitions from 0 to 1 between passbands and stop //bands; the second (response hst2) with one sample in each //transition band (amplitude 0.5) for smoothing. // hd=[zeros(1,15) ones(1,10) zeros(1,39)];//desired samples hst1=fsfirlin(hd,1);//filter with no sample in the transition hd(15)=.5;hd(26)=.5;//samples in the transition bands hst2=fsfirlin(hd,1);//corresponding filter pas=1/prod(size(hst1))*.5; fg=0:pas:.5;//normalized frequencies grid plot2d([1 1].*.fg(1:257)',[hst1' hst2']); // 2nd example hd=[0*ones(1,15) ones(1,10) 0*ones(1,39)];//desired samples hst1=fsfirlin(hd,1);//filter with no sample in the transition hd(15)=.5;hd(26)=.5;//samples in the transition bands hst2=fsfirlin(hd,1);//corresponding filter pas=1/prod(size(hst1))*.5; fg=0:pas:.5;//normalized frequencies grid n=prod(size(hst1)) plot(fg(1:n),hst1); plot2d(fg(1:n)',hst2',[3],"000");
G. Le Vey
| << frmag | group >> |