* Real valued signal is a signal which assumes a real value for its amplitude for all instants of time.* Examples are, cosω

_{o}t, rect(t), u(t), r(t), δ(t), e

^{at }(a is a real value).

* Complex valued signal is a signal which assumes a complex value for its amplitude atleast at one instant of time.* Example is e

^{jωot}

Since e^{jωot }= cosω_{o}t + jsinω_{o}t

*1. If f(t) is a real signal then it satisfies the following relationship*

**f(t) = f ^{*}(t)**

( f^{*}(t) is the conjugate of f(t) )

**Note: **If f(t) = a + jb

then

f^{*}(t) = (a + jb)^{*}

f^{*}(t) = a − jb

*2. If f(t) is a purely imaginary signal then it satisfies the following relationship*

**f(t) = − f ^{*}(t)**