Z1202 wrote:What is easy to forget here is that the mixing coefficients are not the polynomial coefficients in terms of s. You need a polynomial in terms of (s+1), which gives (q-1)^4+2(q-1)^2+1=q^4-4q^3+8q^2-8q+4, where s+1=q, s=q-1. Almost fell for the same trap myself

After rereading our conversation for several times and recalculating lots of stuff I finally got my enlightenment and now I understand what you mean There's been a misunderstanding initially, maybe I didn't write it in a clear way yesterday, idk.

Yes, of course on the left I have q-1 raised to some power, and only after that I open the brackets and rearrange That's what I did from the very beginning. However initially those 1 0 2 0 1 coeffs were indeed a result of a mistake. I mentioned them for the second time only because it's a funny mode.

Edit: But naturally the correct peak received from 1 + s^2/(1 + s)^4 sounds way better.