Direct method for generation of FM signal - Drawbacks & Advantages

Drawbacks of using direct method for generation of FM signal are

Options:

a) Does not give high stability to FM signal frequency
b) Distorted FM signal is generated due to harmonics of modulating signal
c) Cannot be used for high power FM generation
d) Both a) and b)

Correct Answer: d) Both a) and b)

Explanation:

In direct method of FM generation, as the carrier generation is directly affected by the modulating signal, it is not easy to get high order stability in carrier frequency. The non linear characteristics of varactor diode produce a distorted FM signal due to harmonics in the modulating signal.

Advantage of using direct method for generation of FM signal is

Options:

a) It gives high stability to FM signal frequency
b) Distortion free FM signal is generated
c) high power FM generation is possible
d) none of the above

Correct Answer: c) high power FM generation is possible

Explanation:

The direct method for FM generation is advantageous as it may be used for high power FM generation in several applications. Since there is direct generation of FM carrier in accordance with the modulating signal, the direct method is a cheaper method for generation of FM.