Definition

The easiest way to think of time invariance is to use the vertical and horizontal line test. x(t) is the horizontal axis and y(t) is the vertical axis.

x(t) --> system 1 --> y(t)

Vertical ECE301Fall2008mboutin.jpg

Horizontal ECE301Fall2008mboutin.jpg

Time Invariant System

$ y=exp(x) $ This function passes both the horizontal and vertical line tests. TI ECE301Fall2008mboutin.jpg

Non-Time Invariant System

$ y=x^2 $ This function fails the horizontal line test. NonTI ECE301Fall2008mboutin.jpg

Alumni Liaison

Correspondence Chess Grandmaster and Purdue Alumni

Prof. Dan Fleetwood