# Lecture 23 Blog, ECE438 Fall 2014, Prof. Boutin

Monday October 20, 2014 (Week 9) - See Course Outline.

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Today we started Section 7 of the course, on DT signal filtering and z-transforms. We first reviewed a few properties of systems and LIT systems. This brought up the topic of frequency response and transfer function. In order to understand the transfer function and its relationship to the frequency response, we need to study the z-transform of a DT signal. We thus finished the lecture by introducing the z-transform formula and observed its similarity to the DTFT formula. More precisely, we noticed that the DTFT is a restriction of the z-transform to the unit circle.

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