Question

Write any two factors 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.

Answer 1

The need of modulation for transmission of a signal are below-

For transmission of low frequency antenna of height 4-5 km is needed and which is

not feasible so, we need to modulate wave in order to reduce height of antenna to a reasonable height.

For low wave length or high frequency wave effective power radiated by antenna is represented as,

$P\alpha \frac{1}{{\lambda }^2}$

So, to produce effective radiation by antenna, there is a need of modulate wave.