Question

Define the term ‘amplitude modulation’. Explain any two factors which justify the need for modulating a low frequency base-band signal.

Answer 1

Amplitude Modulation:

• Modulation of the amplitude of a radio carrier wave in accordance with the strength of audio or other signal.
• The message signal is super imposed on the carrier wave and the modulated wave is transmitted.

Any two factors which justify the need for modulating a low frequency base-band signal:

• Signals with low frequency are not suitable for long distance transmission due to low attenuation because they have low energies and thus need for modulation arises.
• For large antennas, transmission and for reception of the signal ,ust be comparable to the wavelength of the signal which is not feasible and practically not possible. So it depends on the size of antennas.