Communication Systems

Exercise: Communication Systems

VSB modulation is preferred in TV because

it reduces the bandwidth requirement to half

it avoids phase distortion at low frequencies

it results in better reception

none of the above

Answer: A

VSB (vestigial side band) transmission transmits one side band fully and the other side band partially thus, reducing the bandwidth requirement.

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A modem is classified as low speed if data rate handled is

upto 100 bps

upto 250 bps

upto 400 bps

upto 600 bps

Answer: D

When data rate in bits per second is upto 600, modem is low speed.

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For attenuation of high frequencies we should use

shunt capacitance

series capacitance

inductance

resistance

Answer: A

Since X_c for high frequencies is low, the high frequencies are shunted to ground and are not transmitted.

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A cordless telephone using separate frequencies for transmission in base and portable units is known as

duplex arrangement

half duplex arrangement

either (a) or (b)

neither (a) nor (b)

Answer: A

Separate frequencies for transmission from base and portable units allows two way transmission and is called duplex arrangement.

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