COMMUNICATION SYSTEMS QUIZ

An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.

102.3

70.2

80.9

113

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In Modulation, “carrier” is

Voltage for which frequency, phase or amplitude is varied

Resultant wave

Voltage with constant frequency, phase or amplitude

Speech voltage to be transmitted

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In Pulse Code Modulation system

Suffers from the disadvantage of its incompatibly with TDM

Quantising noise can be reduced by decreasing the number of standard levels

Quantising noise can be overcome by companding

Large bandwidth is required

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The modulation index of an FM is changed from 0 to 1. How does the transmitted power change?

Remains unchanged

Gets increased by 50 percent

Gets doubled

Gets halved

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In EM waves, polarization

Is due to transverse nature of waves

Is always vertical in an isotropic medium

Is caused by reflection

Results from longitudinal nature of waves

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The frequency range of 300 kHz to 3000 kHz is known as

High frequency

Medium frequency

Very high frequency

Low frequency

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A three stage telephone switching structure is to have 128 input and 128 output terminals. There are 16 first stage and 16 third stage matrices. To avoid blocking the number of intermediate paths required is

16

1

8

15

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

Upto 600 bps

Upto 250 bps

Upto 100 bps

Upto 400 bps

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Which one of the following is analog?

Differential PCM

PCM

PWM

Delta modulation

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To eliminate ghosts in the picture

Twist the transmission line

Use a longer transmission line

Change the antenna orientation of location

Connect a booster

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