Which diode helps in FM generation among the following ?

Which diode helps in FM generation among the following ?

a. PIN Diode
b. Varactor Diode
c. Shockley Diode
d. All of these

Correct Answer : b. Varactor Diode

Explanation :

Varactor diode is definitely a semi-conductor diode whose junction capacitance shows variations in accordance to the variations of DC bias voltage. However, it should be connected in shunt with the tuned circuit of carrier oscillator from configurational point of view especially for FM generation.