# Lecture 24 Blog, ECE438 Fall 2011, Prof. Boutin

Wednesday October 18, 2011 (Week 9) - See Course Outline.

Today we went over the solution of the first midterm. After that, we discussed the problem of uniquely defining a system using a constant coefficient difference equation. We observed that specifying that the system is causal gives us enough boundary conditions to uniquely specify the system. We also observed that the transfer function of causal systems defined by constant coefficient difference equation is the outside of a circle in the complex plane, more specifically the circle going through the pole of largest magnitude.

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