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| author | Brijeshcr | 2017-11-30 18:27:20 +0530 |
|---|---|---|
| committer | Brijeshcr | 2017-11-30 18:27:20 +0530 |
| commit | c257cd7a7e766fb89332cca4fb367904767362ed (patch) | |
| tree | 8f455c21cddfd7856cb53c9436319b2c68e4ab50 /macros/invfreqz.sci | |
| parent | cc5c7ee42c6cb2ab94dd0e0f6985778657ab47f5 (diff) | |
| download | FOSSEE-Signal-Processing-Toolbox-c257cd7a7e766fb89332cca4fb367904767362ed.tar.gz FOSSEE-Signal-Processing-Toolbox-c257cd7a7e766fb89332cca4fb367904767362ed.tar.bz2 FOSSEE-Signal-Processing-Toolbox-c257cd7a7e766fb89332cca4fb367904767362ed.zip | |
Help files and functions
Diffstat (limited to 'macros/invfreqz.sci')
| -rw-r--r-- | macros/invfreqz.sci | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/macros/invfreqz.sci b/macros/invfreqz.sci new file mode 100644 index 0000000..d051499 --- /dev/null +++ b/macros/invfreqz.sci @@ -0,0 +1,94 @@ +function [B,A,C] = invfreqz(H,F,nB,nA,W,iter,tol,trace) +//Fit filter B(z)/A(z)to the complex frequency response H at frequency points F. A and B are real polynomial coefficients of order nA and nB. +//Calling Sequence +//[B,A,C] = invfreqz(H,F,nB,nA,W,iter,tol,trace) +//[B,A,C] = invfreqz(H,F,nB,nA,W) +//[B,A,C] = invfreqz(H,F,nB,nA) +//Parameters +//H: desired complex frequency response. +//F: frequency (must be same length as H). +//nB: order of the numerator polynomial B. +//nA: order of the denominator polynomial A. +//W: vector of weights (must be same length as F). +//Description +//This is an Octave function. +//Fit filter B(z)/A(z)to the complex frequency response H at frequency points F. A and B are real polynomial coefficients of order nA and nB. +//Optionally, the fit-errors can be weighted vs frequency according to the weights W. +//Note: all the guts are in invfreq.m +//Examples +//[B,A] = butter(4,1/4); +//[H,F] = freqz(B,A); +//[Bh,Ah,C] = invfreq(H,F,4,4) +//Bh = +// +// 0.010209 0.040838 0.061257 0.040838 0.010209 +// +//Ah = +// +// 1.00000 -1.96843 1.73586 -0.72447 0.12039 +// +//C = -7.7065e-15 + +funcprot(0); +lhs = argn(1) +rhs = argn(2) +if (rhs < 4 | rhs > 8) +error("Wrong number of input arguments.") +end + +select(rhs) + + case 4 then + if(lhs==1) + B = callOctave("invfreqz",H,F,nB,nA) + elseif(lhs==2) + [B, A] = callOctave("invfreqz",H,F,nB,nA) + elseif(lhs==3) + [B, A, C] = callOctave("invfreqz",H,F,nB,nA) + else + error("Wrong number of output argments.") + end + + case 5 then + if(lhs==1) + B = callOctave("invfreqz",H,F,nB,nA,W) + elseif(lhs==2) + [B, A] = callOctave("invfreqz",H,F,nB,nA,W) + elseif(lhs==3) + [B, A, C] = callOctave("invfreqz",H,F,nB,nA,W) + else + error("Wrong number of output argments.") + end + case 6 then + if(lhs==1) + B = callOctave("invfreqz",H,F,nB,nA,W,iter) + elseif(lhs==2) + [B, A] = callOctave("invfreqz",H,F,nB,nA,W,iter) + elseif(lhs==3) + [B, A, C] = callOctave("invfreqz",H,F,nB,nA,W,iter) + else + error("Wrong number of output argments.") + end + case 7 then + if(lhs==1) + B = callOctave("invfreqz",H,F,nB,nA,W,iter,tol) + elseif(lhs==2) + [B, A] = callOctave("invfreqz",H,F,nB,nA,W,iter,tol) + elseif(lhs==3) + [B, A, C] = callOctave("invfreqz",H,F,nB,nA,W,iter,tol) + else + error("Wrong number of output argments.") + end + case 8 then + if(lhs==1) + B = callOctave("invfreqz",H,F,nB,nA,W,iter,tol,trace) + elseif(lhs==2) + [B, A] = callOctave("invfreqz",H,F,nB,nA,W,iter,tol,trace) + elseif(lhs==3) + [B, A, C] = callOctave("invfreqz",H,F,nB,nA,W,iter,tol,trace) + else + error("Wrong number of output argments.") + end + end +endfunction + |