Extracting filter coefficients from fdatool IIR filter object

Thread Starter


Joined Mar 26, 2017
Hi everyone,

I have designed an IRR filter in fdatool but since I can't export the coefficients as a vector into the workspace, I exported the filter as an object. The problem is that when I open the object, I have 3 arrays stored in it (ScaleValues, States and sosMatrix). Please, could someone exlplain me the difference between each array and, more importantly, how I can extract the filter coefficients from my IRR filter ? Also if you could write down links to official sources/documentation, it would amazing. Please any help would be really appreciated. Thank you in advance.

P.S. I am converting my structure to Direct-Form 1since, supposedly, it gives the coefficients for the ideal IRR filter or is, at least, more accurate but I am also not sure about it and if soemone could also explain me what it is exactly, it would be greatly appreciated.

Also, I am using a Lowpass Chebyshev Type II filter for my IIR. Thank you.
Last edited: