diff options
Diffstat (limited to 'macros/sos2ss.sci')
| -rw-r--r-- | macros/sos2ss.sci | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/macros/sos2ss.sci b/macros/sos2ss.sci index c13f688..d629c29 100644 --- a/macros/sos2ss.sci +++ b/macros/sos2ss.sci @@ -1,5 +1,27 @@ //Author: Parthasarathi Panda //parthasarathipanda314@gmail.com +//Convert digital filter second-order section parameters to state-space form +//Calling Sequence +//[A,B,C,D] = sos2ss(sos) +//[A,B,C,D] = sos2ss(sos,g) +// +//sos2ss converts a second-order section representation of a digital filter to an equivalent state-space representation. +//A,B,C,D:Steady state parameters +//sos:6 column second order section matrix +//g:gain + + +//EXAMPLES: +//sos = [1 1 1 1 0 -1 ; +// -2 3 1 1 10 1]; +//[A,B,C,D] = sos2ss(sos,2); +// +//EXPECTED OUTPUT: +//D =- 4. + //C =42. 4. - 32. - 2. + //B =[1. 0. 0. 0. 0.]' + //A =[- 10. 0. 10. 1. ; 1. 0. 0. 0. ; 0. 1. 0. 0. ; 0. 0. 1. 0. ] + function [A,B,C,D]=sos2ss(sos,g) [nargout,nargin]=argn(); if nargin==1 then @@ -16,7 +38,7 @@ function [A,B,C,D]=sos2ss(sos,g) if j~=6 then error('sos should be a 6-column matrix'); end - + num=[1]; den=[1]; //convolving the numerator and denominator to get the coefficient of the numerator and the denominator at the top and bottom @@ -24,21 +46,21 @@ function [A,B,C,D]=sos2ss(sos,g) num=convol(num,sos(i,1:3)); den=convol(den,sos(i,4:6)); end - + t=2*d+1; //polynomial degree must be defined here if den(t)==0 then error('improper transfer function check input'); end - - t=2*d+1; //polynomial degree + + // t=2*d+1; //polynomial degree A=zeros(t-1,t-1); if t>2 then A(2:(t-1),1:(t-2))=eye(t-2,t-2); end - A(1,:)=-1*den(2:t)/den(1); + A(1,:)=-1*den(2:t)/den(1); B=zeros(t,1); B(1)=1/den(1); //constructing (A,B) in canonical controllable form C=g*(num(2:t)-den(2:t)*num(1)/den(1));//appropiate C and D D=g*num(1)/den(1); - + endfunction |