Thread Subject:

problem using resid

Hi,

i have to validate a estimated arx model. I try to use resid command but it gives me the following error:

the resid returns me the following error:

??? Error using ==> utresid at 199
Resid cannot be applied to Continuous Time data.

Error in ==> idmodel.resid at 54
    utresid(v{:});

I use resid command in this way:

hpidfrd=idfrd(hp,2*pi*fp,0);
modarx=arx(hpidfrd,[num+1 den])
resid(hpidfrdiddata,modarx)

fp: frequency value
hp: complex transfer function value
num e den: arx model orders

How can i perform a residual analysis with Continuous Time data?