## Periodic Signal

Periodic Signals are signals that repeat themselves after a certain amount of time. More formally, a function

*f(t)*is periodic if*f(t + T) = f(t)*for some*T*and all*t*. The classic example of a periodic function is*sin(x)*since*sin(x + 2 π) = sin(x)*. However, we do not restrict attention to sinusoidal functions.