Documentation of sett

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Function Synopsis

thn=sett(th,T);

Help text

SETT   Sets the sampling interval in TH-structures and frequency functions.
   THN = sett(TH,T)  or GN = sett(G,T)

   TH:  The original model in THETA-format
   T:   The sampling interval
   THN: The new model in THETA-format, with sampling interval T
   or
   G:   The original frequency function
   GN:  The frequency function with frequencies scaled according to
        the desired sampling interval
   For frequency functions SETT works only for functions generated by
   (see also) SPA, ETFE, TH2FF, or TRF, with a default choice of
   frequencies. See also FREQFUNC.

Cross-Reference Information

Listing of function sett

function thn=sett(th,T);

%   L. Ljung 10-2-90
%   Revised 21-4-91
%   Copyright (c) 1986-98 by The MathWorks, Inc.
%   $Revision: 2.3 $  $Date: 1997/12/02 03:40:40 $

if nargin<2
   disp('Usage: THN = SETT(TH,T)')
   return
end

[nr,nc]=size(th);thn=th;
if nr==129
        test=rem(th(1,:),1000); tt=test(1);
        if floor(tt)==tt & tt>=100 & tt<=119 %Then we have freqfunc case
        freqind=find(test>=100);
        spind=find(test==0);sdind=find(test==50);frspind=find(test==100);
        Tcurrent=(ones(1,length(freqind))*pi)./th(129,freqind);
        Tspc=(ones(1,length(frspind))*pi)./th(129,frspind);
        thn(2:129,freqind)=thn(2:129,freqind).*(ones(128,1)*Tcurrent)/T;
        if ~isempty(spind)
          thn(2:129,spind)=thn(2:129,spind)./(ones(128,1)*Tspc)*T;
        end
        if ~isempty(sdind)
          thn(2:129,sdind)=thn(2:129,sdind)./(ones(128,1)*Tspc)*T;
        end
end,else
if isthss(th),if any(th(2,8)==[1 5]),thn(1,2)=-abs(T);else thn(1,2)=T;end,
else
thn(1,2)=T;
end
end