Frequency Modulation

Which of the following indicates the degree to which a signal is modulated?

• Frequency deviation

• Modulation index

• Deviation ratio

• Carson’s rule

The ability of an FM receiver to receive the strongest signal and reject others

• sensitivity

• selectivity

• Capture effect

• Flywheel effect

In FM, the frequency deviation rate is equal to

• Δf

• m

• f_c

• f_m

Indirect frequency modulation can be used using

• Balanced modulator

• Voltage controlled oscillator

• discriminator

• Phase modulator

In frequency modulation, the frequency deviation varies according to the _____________ of the modulating signal

• amplitude

• Instantaneous value

• frequency

• Frequency and phase

Which of the following is NOT true in FM?

• The peak amplitude of the carrier remains constant

• The bandwidth is larger compared to AM

• The frequency of the carrier is directly proportional to the amplitude of the modulating signal

• It is more resistant to noise than AM

The modulation index in FM is NOT a function of

• The modulating signal amplitude

• Carrier frequency

• Modulating signal frequency

• Frequency deviation

Which is an important circuit in generating FM?

• PLL

• Differential amplifier

• VCO

• 555 timer

Phase modulators are not widely used in FM broadcasting because

• The simply don’t produce FM because they produce PM signals

• They are rather costly to implement

• They are inefficient and less stable

• They produce limited frequency deviation

The power amplifier in FM can be nonlinear because

• There are no peak amplitude variations in the envelop

• It reduces the noise

• The efficiency is much higher

• No! the amplifier should be linear!