Q.1
When the length of antenna is a whole wavelength
Q.2
For telegraphy the most commonly used modulation system is
Q.3
The main function of a balanced modulator is to
Q.4
Under ordinary circumstances, impulse noise can be reduced in
Q.5
Which of the following is used to generate PDM?
Q.6
In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then
Q.7
Full duplex operation permits transmission in both directions at the same time.
Q.8
A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be
Q.9
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
Q.10
For a low level AM system, the amplifiers modulated stage must be
Q.11
In case of low level amplitude modulation system, the amplifiers following the modulated stage must be
Q.12
The colour of an object is decided by
Q.13
Commercial Frequency deviation of FM is
Q.14
An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.
Q.15
A cordless telephone using separate frequencies for transmission in base and portable units is known as
Q.16
In TV systems, equalising pulses are sent during
Q.17
For a given carrier wave, maximum undistorted power is transmitted when value of modulation is
Q.18
The modulation index of an FM is changed from 0 to 1. How does the transmitted power change?
Q.19
To eliminate ghosts in the picture
Q.20
Circular polarization
Q.21
The disadvantage of FM over AM is that
Q.22
VSB modulation is preferred in TV because
Q.23
Which of the following is a digital modulation technique?
Q.24
Assertion (A): In FM the frequency of the carrier is varied by the modulating voltage
Reason (R): FM and PM are two forms of angle modulation.
Q.25
The maximum power output of a standard A earth station over the total band allocated to satellite communication is about
Q.26
If in a broadcasting studio, a 1000 kHz carrier is modulated by an audio signal of frequency range 100-5000 kHz, the width of channel is __________ kHz.
Q.27
In Modulation, “carrier” is
Q.28
Which one of the following is analog?
Q.29
PAM stands for
Q.30
A telephone channel requires a bandwidth of about
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