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  • Committer: Bazaar Package Importer
  • Author(s): Torsten Werner
  • Date: 2002-03-21 16:57:43 UTC
  • Revision ID: james.westby@ubuntu.com-20020321165743-e9mv12c1tb1plztg
Tags: upstream-2.6
Import upstream version 2.6

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man/control/specfact.cat
 
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specfact          Scilab Group          Scilab Function            specfact
 
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NAME
 
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   specfact - spectral factor
 
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CALLING SEQUENCE
 
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 [W0,L]=specfact(A,B,C,D)
 
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DESCRIPTION
 
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   Given a spectral density matrix phi(s):
 
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                  -1                   -1
 
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      R + C*(s*I-A) * B  +  B'*(-s*I-A') * C'  with R=D+D' > 0
 
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   specfact computes  W0 and L such  that  W(s)=W0+L*(s*I-A)^-1*B  is a
 
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  spectral factor of of PHI(s), i.e.
 
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   phi(s)=W'(-s)*W(s)
 
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EXAMPLE
 
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 A=diag([-1,-2]);B=[1;1];C=[1,1];D=1;s=poly(0,'s');
 
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 W1=syslin('c',A,B,C,D);
 
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 phi=gtild(W1,'c')+W1;
 
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 phis=clean(ss2tf(phi))
 
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 clean(phis-horner(phis,-s)');   //check this is 0...
 
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 [A,B,C,D]=abcd(W1);
 
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 [W0,L]=specfact(A,B,C,D);
 
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 W=syslin('c',A,B,L,W0)
 
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 Ws=ss2tf(W);
 
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 horner(Ws,-s)*Ws
 
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SEE ALSO
 
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   gtild, sfact, fspecg
 
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AUTHOR
 
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   F. D. 
 
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