Periodic versus non-periodic functions (hw1, ECE301)

Read the instructor's comments here.

Periodic Signal

Above is an example of a periodic signal: $ y(t) = \sin(\pi t) $

The function is periodic because as can be seen from the graph $ y(t+T)= y(t) $ where T=2 seconds.

Non-Periodic Signal

Represented above is an example of a non-periodic function: $ y(t)=sin(10 \pi \ln(t)) $. This function is clearly not periodic because the frequency changes with time and therefore $ y(t+T)\ne y(t) $.