Digital Communications

Modulation is done in

• radio receiver

• transmitter

• between transmitter and receiver

• None of the above

In an AM wave the majority of the power is in

• lower sideband

• Carrier

• Upper Sideband

• None of the above

Modulation refers to a low frequency signal controlling the

• amplitude of the carrier

• frequency of the carrier

• phase of the carrier

• any of the above

Noises are variations in

• amplitude

• frequency

• phase

• both phase and frequency

If level of modulation is increased ................ power is increased.

• carrier

• carrier as well as sideband

• sideband

• None of the above

At 100% modulation the power in each sideband is ............ of that of carrier.

• 50%

• 40%

• 60%

• 25%

Overmodulation results in

• weakening of the signal

• excessive carrier power

• distortion

• none of the above

The major advantage of FM over AM is

• reception is less noisy

• higher carrier frequency

• smaller bandwidth

• small frequency deviation

Which are the additional stages in FM receiver

• AF amplifier

• limiter

• descriminator

• selector

• None of the above

The antenna length is smaller for FM broadcasting because the wavelength of FM is short

• True

• False