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transfer functions
Posted:
Jul 16, 1997 6:42 AM


I've recently tried to find coefficients for a simple, linear model like
my''+ cy' + ky = ax, where
y is output, x is input and m, c, k and a are constants.
From Bendat & Piersol one learns that a H(f)=  , k  (2*pi*f)^2 + i*2*pi*f*c
for a unit impulse.
From experiments I have H(f), I want to find a,k and c.
In matlab there is a toolbox for control systems, and there is for instance a function called tf.
Is there anyone who knows if it is possible to convert a transfer function numerically, either as a complex vector or as a magnitude and phase vector, to a denominator and numerator which describes i.e. the state space model in the mentioned toolbox?  Ole M. Damlien Parkveien 14 5007 Bergen
Tlf. 55 903442 Ole.Damlien@gfi.uib.no



