Q.1.
In Pulse Code Modulation system
Q.2.
A modem is classified as low speed if data rate handled is
Q.3.
The main function of a balanced modulator is to
Q.4.
Which of the following does not cause losses in optical fibre cables?
Q.5.
A buffer amplifier is
Q.6.
Commercial Frequency deviation of FM is
Q.7.
If output power of a radio receiver is doubled, its volume is increased by __________ dB.
Q.8.
Which of the following is used to generate PDM?
Q.9.
When the length of antenna is a whole wavelength
Q.10.
Which of the following is a digital modulation technique?
Q.11.
For telegraphy the most commonly used modulation system is
Q.12.
The disadvantage of FM over AM is that
Q.13.
A telephone channel requires a bandwidth of about
Q.14.
Which of the following is an indirect way of generating FM?
Q.15.
One of the advantages of base modulation over collector modulation of a transistor class C amplifier is
Q.16.
The maximum power output of a standard A earth station over the total band allocated to satellite communication is about
Q.17.
As per Shannon-Hartley theorem, a noise less Gaussian channel has
Q.18.
An audio signal (say fromHz toHz) is frequency translated by a carrier having a frequency ofHz. The values of initial (without frequency translation) and final (after frequency translation) fractional change in frequency from one band edge to the other are
Q.19.
Skip distance depends on time of day and angle of incidence.
Q.20.
In practical commercial FM system, channel bandwidth is
Q.21.
If sampling is done at the rate ofkHz. The bandwidth required is
Q.22.
In EM waves, polarization
Q.23.
It is found that a ship to ship communication suffers from fading. This can be avoided by using
Q.24.
An FM radio receiver which is tuned to a 91.6 MHz broadcast station may receive an image frequency of __________ MHz.
Q.25.
In case of low level amplitude modulation system, the amplifiers following the modulated stage must be
Q.26.
For a low level AM system, the amplifiers modulated stage must be
Q.27.
A three stage telephone switching structure is to haveinput andoutput terminals. There arefirst stage andthird stage matrices. To avoid blocking the number of intermediate paths required is
Q.28.
A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidthkHz. The output of the samples so obtained would be
Q.29.
Under ordinary circumstances, impulse noise can be reduced in
Q.30.
In a FM receiver, amplitude limiter