Periodic and Nonperiodic Signals

A continuous-time signal x ( t ) is said to be periodic with period T if there is a positive
nonzero value of T for which

x(t + T ) = x ( t ) all t

An example of such a signal is given in fig. From Eq it follows
that

x (t+ mT) = x(t)

for all t and any integer m. The fundamental period T, of x ( t ) is the smallest positive
value of T for which Eq holds. Note that this definition does not work for a constant