"Glitches" in transfer function
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Hi all,
I was developing a certain model which includes a lot of transfer functions, which are mainly 2x2 matrices. There is a fair deal of multiplication and division of these transfer function as well. I have noticed that in some of them I have sort of "glitches" which I have no idea how to avoid and correct. Have you seen similar behaviour or, even better, you have a solution for it? Below is the what I obtain when I draw the transfer function with "bodeplot" command
3 Comments
Bruno Luong
on 16 Jul 2019
FIR order 68? It's not surprising that you run into numerical problem with such high order.
Accepted Answer
Star Strider
on 16 Jul 2019
Precision could certainly be a problem, especiall considering the magnitudes of those numbers. (MATLAB retains full internal precision, even though the printed output is much less precise.)
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Star Strider
on 16 Jul 2019
The minreal function can solve many problems.
Symbolic functions have the advantage of extended precision, however to use those results with the Control System Toolbox functions, you would then have to use the double function to get the symbolic results in a form it can use. It is not easy to use symbolic functions to model control systems, since you need to write the necessary functions yourself. Also, the Symbolic Math Toolbox is not ideal for problems requiring recursive solutions, such as loops. It can take forever.
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