ss2tf

conversion from state-space to transfer function

Calling Sequence

[h]=ss2tf(sl)
[Ds,NUM,chi]=ss2tf(sl)

[h]=ss2tf(sl,"b")
[Ds,NUM,chi]=ss2tf(sl,"b")


[h]=ss2tf(sl,rmax)
[Ds,NUM,chi]=ss2tf(sl,rmax)

Arguments

:sl linear system ( syslin list) : :h transfer matrix :

Description

Called with three outputs [Ds,NUM,chi]=ss2tf(sl) returns the numerator polynomial matrix NUM, the characteristic polynomial chi and the polynomial part Ds separately i.e.:

h = NUM/chi + Ds

Method:

One uses the characteristic polynomial and det(A+Eij)=det(A)+C(i,j) where C is the adjugate matrix of A.

With rmax or “b” argument uses a block diagonalization of sl.A matrix and applies “Leverrier” algorithm on blocks. If given, rmax controls the conditionning (see bdiag).

Examples

s=`poly`_(0,'s');
h=[1,1/s;1/(s^2+1),s/(s^2-2)]
sl=`tf2ss`_(h);
h=`clean`_(ss2tf(sl))
[Ds,NUM,chi]=ss2tf(sl)

See Also

• tf2ss transfer to state-space
• syslin linear system definition
• nlev Leverrier’s algorithm
• glever inverse of matrix pencil