Question
Distinguish between frequency modulation and amplitude modulation. Why is an FM signal less susceptible to noise than AM signal?
Solution
Amplitude modulation:
- The modulation technique is comparitively simple and instruments are cheap.
- The modulated signal's amplitude varies as per the modulating signal.
Frequency modulation:
- Modulation instruments and techniques are more costly and complex than AM.
- The modulated signal's frequency varies as per the modulating signal.
- It is less noisy and gives better quality transmission and has a larger bandwidth.
The noise in any signal is related to the amplitude variation of the signal emitted by a source. In FM, only frequency changes and amplitude remains constant. Therefore, FM signal is less susceptible to noise than an AM signal.
