In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then
A)amplitude of distant sidebands decreases
B)amplitude of distant sidebands increases
C)amplitude of distant sidebands remains constant
D)amplitude of distant sidebands first increases, then decreases

Question

Quizplus · Accepted Answer

In frequency modulation (FM), when the modulating frequency is lowered while keeping the modulating voltage constant, the spacing between the sidebands increases. However, the amplitude of the distant sidebands increases because the modulation index (which is proportional to the ratio of the modulating voltage to the modulating frequency) increases, leading to stronger sidebands further away from the carrier frequency.

In Case of Frequency Modulation, Modulating Voltage Remains Constant If