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ms
Posts:
61
Registered:
11/6/06


ETFE function questions
Posted:
Mar 21, 2011 12:16 PM


I am trying to use the ETFE function, but was wondering if someone could help explain what is happening when performing this function.
The original function is:
A = etfe(data,M,N), when data is a form of iddata, M is a smoothing operation, and N is the number (128 default) equally spaced frequencies between 0 (excluded) and pi.
By looking at A in the editor, I see this:
IDFRD model G. Contains Frequency Response Data for 1 output and 1 input at 128 frequency points, ranging from 2.4544 rad/s to 314.16 rad/s.
My question is, how does changing N affect the interpretation of data. For example, when I plot a bode diagram using the data, I clearly see as N increases, I have more data points on the x axis (frequency). Also, when looking at the editor, the frequency ranges changes too. Should the value used for N be a function of the length of the "data" vector? Does it matter if the data vector is smaller or larger than N?
Thanks!



