A Periodic Function
A very obvious periodic CT function is sin(t + T). The definition of a periodic function is a function which will have the same value at x(t) as at x(t + T) when T > 0. An example of T for a sin function would be any multiple of 2*pi. This is due to a sine wave's nature as it always returns the same value when shifted by 2*pi.
Periodic Function Example
View the following picture for a clear view. Media: PeriodicWave_ECE301Fall2008mboutin.jpg
Non-Periodic Function
A non-periodic function is any function x(t) that does not fulfill x(t) = x(t + T) for any T. An example of a non-periodic function would be t^2. The only thing adding T to t^2 would cause would be a time shift and it would never repeat all values the same as the previous t^2.
