# From filter diagram to state equation

How did we end up with these state variables $$Z_1(n+1)$$ and $$Z_2(n+1)$$ from the filter diagram ?

New contributor
JasonB is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
• It's unclear to me what exactly it is that you don't understand. – Matt L. Feb 11 at 11:28
• @MattL. How exactly did we come to derive the equations from the filter, I do understand half of it is from the feedback part, and rest feed forward, but I am confused regarding the flow of signals thats yield the Z1(n+1) and Z2(n+1). – JasonB Feb 11 at 12:08
• Some arrows would help in the diagram. Note that the bottom path goes from right to left. And the path between the adders is from left to right. A delay makes from $z_i[n+1]$ a signal $z_i[n]$ (and not the other way around). – Matt L. Feb 11 at 13:00
• @MattL. Makes sense, thank you for your time, I am beginning to understand it now. – JasonB Feb 11 at 13:15