Modulation & Demodulation

What is the primary purpose of modulation in radio transmission?

• To eliminate noise from the signal

• To allow audio signals to be transmitted over long distances

• To reduce the size of the transmitting antenna

• To increase the audio signal power

What is the modulation factor in amplitude modulation?

• The ratio of the carrier power to the total power

• The ratio of the carrier frequency to the signal frequency

• The ratio of the signal amplitude to the carrier amplitude

• The ratio of the audio frequency to the carrier frequency

What happens to the power in sidebands when modulation increases?

• It decreases

• It remains constant

• It increases

• It becomes negligible

In a superhetrodyne receiver, what is the purpose of the mixer stage?

• To filter out noise

• To demodulate the signal

• To convert the radio frequency to an intermediate frequency

• To amplify the audio signal

What is the typical intermediate frequency (IF) for AM receivers?

• 455 kHz

• 10.7 MHz

• 1 MHz

• 100 kHz

What is the main advantage of frequency modulation over amplitude modulation?

• Lower bandwidth requirements

• Less susceptibility to noise

• Higher power consumption

• Simpler receiver design

What is the effect of overmodulation in amplitude modulation?

• Improved sound quality

• Reduced power consumption

• Signal distortion

• Increased transmission range

What is the typical frequency range for FM broadcasting?

• 100 kHz to 1 MHz

• 1 MHz to 10 MHz

• 540 kHz to 1600 kHz

• 88 MHz to 108 MHz

In frequency modulation, what does the modulation index represent?

• The ratio of audio signal amplitude to carrier amplitude

• The ratio of carrier frequency to modulating frequency

• The ratio of carrier power to sideband power

• The ratio of frequency deviation to modulating frequency

What is the typical power distribution in an AM wave? Also write the equation.

• Power equally distributed among all frequencies

• Majority of power in sidebands

• Equal power in carrier and sidebands

• All power in the carrier