des2tf

descriptor to transfer function conversion

Calling Sequence

[S]=des2tf(sl)
[Bfs,Bis,chis]=des2tf(sl)

Arguments

:sl list (linear system in descriptor form) : :Bfs, Bis two polynomial matrices : :chis polynomial : :S rational matrix :

Description

Given the linear system in descriptor form i.e. Sl=list(‘des’,A,B,C,D,E), des2tf converts sl into its transfer function representation:

S=C*(s*E-A)^(-1)*B+D

Called with 3 outputs arguments des2tf returns Bfs and Bis two polynomial matrices, and chis polynomial such that:

S=Bfs/chis - Bis

chis is the determinant of (s*E-A) (up to a xcative constant);

Examples

s=`poly`_(0,'s');
G=[1/(s+1),s;1+s^2,3*s^3];
Descrip=`tf2des`_(G);Tf1=des2tf(Descrip)
Descrip2=`tf2des`_(G,"withD");Tf2=des2tf(Descrip2)
[A,B,C,D,E]=Descrip2(2:6);Tf3=C*`inv`_(s*E-A)*B+D

See Also

• glever inverse of matrix pencil
• pol2des polynomial matrix to descriptor form
• tf2des transfer function to descriptor
• ss2tf conversion from state-space to transfer function
• des2ss descriptor to state-space
• rowshuff shuffle algorithm