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From: "Rajiv Singh" <rajiv_singh@msn.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Convert frequency response data to simulink block
Date: Wed, 19 Nov 2008 12:18:06 -0500
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Version 6.0 of System Identification Toolbox introduced frequency domain 
identification. So it will not work with version 5.0

Rajiv


"Gary Pratt" <gp_removethis_@wi.rr.com> wrote in message 
news:gfss5g$ja$1@fred.mathworks.com...
>
>> H = mag.*exp(j*phase);
>> G = idfrd(H,w);  %w is fequency in rad/s
>> (make sure the phase is in rad.)
>>
>> Then you may estimate paramteric models using G as data. If you want
>> continuous-time models, you can set the sample time to zero in G 
>> (G.Ts=0),
>> or use "process models" (see M4 below).
>>
>> M1 = oe(G, [2 2 1]); %get output error model: y = B/F*u+e, with 2 poles 
>> and
>> one zero
>> M2 = pem(G,4); % 4th order state-space model
>> M3 = arx(G, [2 2 1]); %arx model: Ay = Bu+e
>> M4 = pem(G,'p2dz'); % get a continuous-time process model
>
> My version of Matlab doesn't seem to accept IDFRD objects for oe, pem, or 
> arx.  I'm using version MatLab 6.5 and the system identification toolbox 
> version 5.0.  pem() complains that OutputData must be a 2D matrix.  arx() 
> complains that NN must be the same number of columns as inputs.  Am I 
> missing a step, or do I need to user a newer version matlab?