Communication Systems MCQ Questions Answers Electronics Engineering

11) Light travels along the optical fibers by which mechanism ?

a) Refraction

b) Reflection

c) Scattering

d) Total internal reflection

View Answer
Option – d)

12) Quadrature multiplexing is

(a) the same as FDM

(b)the same as TDM

(c) a combination of FDM and TDM

(d)quite different from FDM and TDM

View Answer
Option – d)

13) Which ionosphere layer is responsible for return of a radiation at frequency 30 MHz ?

a) D

b) E

c) F

d) All of above

View Answer
Option – c)

14) Tropospheric scatter communication is used for which frequency band ?

a) HF

b) VHF

c) UHF
d) VLF

View Answer
Option – c)

15) What was the first commercial geostationary communication satellite ?





View Answer
Option – a)

16) Which one of the following photo-detector does not provide gain ?

a) Photo-transistor

b) Photo conductor

c) Avalanche photodiode

d) p-i-n photodiode

View Answer
Option – d)

17) A balanced modulation, is used in the generation of which of the following ?

a) DSB-SC signal

b) FM signal

c) PM signal

d) PAM signal

View Answer
Option – a)

18) Which one of the following is correct ? in a TDM system each signal is alloted in a frame a unique and fixed

a) frequency slot

b) time slot

c) amplitude slot

d) phase slot

View Answer
Option – b)

19) During power measurement the out power measured was -90 dBm. What is the measured power in W ?

a) 1 mW

b) 1 pW

c) 10 W

d) 1 W

View Answer
Option – b)

20) In order to permit the selection of 1 out of 16 equiprobable events, what is the number of bits required ?

a) 8

b) 4

c) log 10 16

d) 2

View Answer
Option – b)
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