UGC-NET 2018: (Communication Systems) SpeedTest Quiz 17 for ESE & GATE EC Exams

Question 1

Time-Division Multiplex

Question 2

Indicate which of the following system is digital?

Question 3

The following items consist of two statements, one labelled the ‘Assertion (A)’ and the other labelled the ‘Reason (R)’. You are to examine these two statements and decide if the Assertion (A) and the Reason (R) are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answers to these items using the codes given below and mark your answer sheet accordingly.

Assertion (A): In optical fibre communication, light rays are guided by the total internal reflection at the interface between fibre core and cladding.
Reason (R): The Refractive Index of core is large than the Refractive Index of cladding.

Question 4

Read the paragraph and answer the question.

Multiplexing is the sending of a separate signals together, over the same cable or bearer simultaneously without interference. Time division multiplex is a method of interleaving in the time domain pulses belonging to different transmissions. These pulses are generally narrow and separation between successive pulses is rather wide. That being the case it is possible, provided the two ends of a link are synchronized, to use the wide spaces for pulses belonging to other transmissions. Frequency division multiplexing concerns itself with combining continuous signals. It may be thought of as an outgrowth of independent side band transmission on a much enlarged scale. As will seen 12 or 16 channels are combined into a group, 5 groups into a subgroup. Each group and subgroup is then sent as a whole unit one microwave link cable or other broadband system. Continental broadband systems are then treated followed by coaxial cables, fibre optic cable, microwave links and troposcatter systems.

A scheme in which several channels are interleaved and then transmitted together is known as

Question 5

Read the paragraph and answer the question.

Multiplexing is the sending of a separate signals together, over the same cable or bearer simultaneously without interference. Time division multiplex is a method of interleaving in the time domain pulses belonging to different transmissions. These pulses are generally narrow and separation between successive pulses is rather wide. That being the case it is possible, provided the two ends of a link are synchronized, to use the wide spaces for pulses belonging to other transmissions. Frequency division multiplexing concerns itself with combining continuous signals. It may be thought of as an outgrowth of independent side band transmission on a much enlarged scale. As will seen 12 or 16 channels are combined into a group, 5 groups into a subgroup. Each group and subgroup is then sent as a whole unit one microwave link cable or other broadband system. Continental broadband systems are then treated followed by coaxial cables, fibre optic cable, microwave links and troposcatter systems.

Broad band long distance communication was originally made possible by the advent of

Question 6

Quantizing Noise occurs in

Question 7

Consider the system with x(t) as input and y(t) as output. The frequency domain characteristics are shown in the figure. Which combination of A and B will give Y as result?

Question 8

In a telecommunication trans-receive system the transmitting antenna with antenna aperture of lm is fed with 1W of power at 10GHz. The receive antenna with antenna aperture of 0.5m located at 1km away receives x mW of power. If the transmitting frequency changes to 20GHz, what will happen to receive power?

Question 9

The signal m(t) as shown is applied both to a phase modulator (with kp as the phase constant) and a frequency modulator with (kf as the frequency constant) having the same carrier frequency. The ratio kp/kf (in rad/Hz) for the same maximum phase deviation is

Question 10

If analog sampling frequency of a band limited signal is doubled then corresponding digital sampling frequency will be