Signal and Antenna

Question

Define the term:

a) Signal.  
b) Antenna.

Answer 1

a) A signal refers to any physical quantity which is carrying the information which varies with the time. The value of signal can be real or complex. Continuous signal and discrete time signal are the types of signal.

b) An antenna or aerial is one or more electrical conductors of the specific length which emit the radio waves produced by the transmitter or which collect the radio waves at receiver.