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// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) INRIA -
//
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution. The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt
function [s1,s2]=sysconv(s1,s2)
//Syntax : [s1,s2]=sysconv(s1,s2)
//
// Converts s1 and s2 into common representation in order that
// system interconnexion operations can be applied.
// The conversion rules in given in the following table.
// 'c' -> continuous time system
// 'd' -> discrete time system
// n -> sampled system with sampling period n
// [] -> system with undefined time domain
//For mixed systems s1 and s2 are put in state-space representation.
//
//
//
// s1\s2| 'c' | 'd' | n2 | [] |
// ---------------------------------------------------------------
// 'c' | nothing |uncompatible | c2e(s1,n2) | c(s2) |
// ---------------------------------------------------------------
// 'd' |uncompatible| nothing | e(s1,n2) | d(s2) |
// ---------------------------------------------------------------
// n1 | c2e(s2,n1) | e(s2,n1) | n1<>n2 uncomp | e(s2,n1) |
// | | | n1=n2 nothing | |
// ---------------------------------------------------------------
// [] | c(s1) | d(s1) | e(s1,n2) | nothing |
// ---------------------------------------------------------------
//
// Meaning:
//n1,n2 -> sampling period
//c2e(s,n) -> the continuous-time system s is transformed into
// a sampled system with sampling period n.
//c(s) -> conversion to continuous (time domain is 'c')
//d(s) -> conversion to discrete (time domain is 'd')
//e(s,n) -> conversion to samples system with period n
//!
s11=s1(1);s21=s2(1);
if s11(1)<>s21(1) then // conversion ss<-->tf
if s11(1)=="r" then s1=tf2ss(s1),else s2=tf2ss(s2),end
s11=s1(1);s21=s2(1);
end;
select s1("dt")
case "c" then t1=0
case "d" then t1=1
case [] then t1=3
else t1=2
end;
select s2("dt")
case "c" then t2=0
case "d" then t2=1
case [] then t2=3
else t2=2
end;
select t1+4*t2
case 0 then,
case 1 then warning(msprintf(gettext("%s: time domains are not compatible.\n"), "sysconv"))
case 2 then s2=dscr(s2,s1("dt"))
case 3 then s1("dt")="c"
case 4 then warning(msprintf(gettext("%s: time domains are not compatible.\n"), "sysconv"))
case 5 then,
case 6 then s2("dt")=s1("dt")
case 7 then s1("dt")="d"
case 8 then s1=dscr(s1,s2("dt"))
case 9 then s1("dt")=s2("dt")
case 10 then
if s1("dt")<>s2("dt") then
warning(msprintf(gettext("%s: time domains are not compatible.\n"), "sysconv"))
end
case 11 then s1("dt")=s2("dt")
case 12 then s2("dt")="c"
case 13 then s2("dt")="d"
case 14 then s2("dt")=s1("dt")
end
endfunction
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