Write any two factor which justify the need for modulating a signal.

Draw a diagram showing an amplitude modulated wave by superposing a modulating signal over a sinusoidal carrier wave.

Two factors justifying the need for modulation are:

(i) Practical size of antenna.

(ii) To avoid mixing up of signals from different transmitters i.e., avoid fluctuation and reduce the noise of signal.

The figures shows how modulated wave is formed by superimposing modulating signal over a carrier wave.