ADVANCE COMMUNICATION SYSYTEM MCQ-2

1. In Sky wave propagtion, propagated waves are refracted from ______

(A) Troposphere
(B) Ionosphere
(C) Stratosphere
(D) None of these

2. Which of the following is line of sight distance, if height of transmitting and receiving antennas are 64 meter each. Consider earth is flat

(A) 57 meter
(B) 57 kilometer
(C) 228 kilometer
(D) 228 meter

3. Which of the following is non-linear modulation technique

(A) A.M
(B) F.M
(C) Both (a) and (b)
(D) None of these

4. Which of the following is example of external noise

(A) Atmospheric noise
(B) Cosmic noise
(C) Shot noise
(D) Both (a) and (b)

5. Shot noise is produced in ______

(A) Semiconductor
(B) Conductor
(C) Both (a) and (b)
(D) None of these

6. Noise figure is always ______ one

(A) Greater than
(B) Less than
(C) Equal to
(D) None of these

7. Satellites operate in the frequency range of

(A) 300 MHz to 3GHz
(B) 3 GHz to 30 GHz
(C) 3 MHz to 30 MHz
(D) None of these

8. Transponder is used to ______

(A) Receive Signal
(B) Transmit Signal
(C) Both (a) and (b)
(D) None of these

9. Which of the following fiber is more resistant to micro-bending loss

(A) Step index fiber
(B) Graded index fiber
(C) Both (a) and (b)
(D) None of these

10. Which of the following is part of optical fiber

(A) Core
(B) Cladding
(C) Coating
(D) All of the above

11. PIN diode can be used as ______

(A) Optical detector
(B) Optical source
(C) Both (a) and (b)
(D) None of these

12. Frequency range of X-band radar is ______

(A) 8 – 12 GHz
(B) 12 – 18 Ghz
(C) 8 – 12 MHz
(D) 18 – 27 GHz

13. If P_T power is fed to an isotropic antenna, then power radiated

(A) PT/R² Watt/m²
(B) PT/R Watt/m
(C) PT/(2πR²)Watt/m²
(D) PT/(4πR²)Watt/m²

14. Which of the following is part of MTI radar

(A) Phase detector
(B) Delay line
(C) Both (a) and (b)
(D) None of these

15. Probabilities of symbols x and y are P(x) and P(y) respectively. Information contents of symbols x and y are I(x) and I(y). Which of the following inequality is correct –

(A) I(x)>I(y) if P(x)>P(y)
(B) I(x)< I(y) if P(x)< P(y)
(C) I(x)>I(y) if P(x)< P(y)
(D) None of these

16. Bit/symbol is unit of ______

(A) Entropy
(B) Information rate
(C) Information content
(D) None of these

17. [P(y/x)]=[[1-P P],[P, 1-P]] is the channel matrix of ______

(A) Lossless channel
(B) Deterministic channel
(C) Noiseless channel
(D) Binary symmetric channel

18. Which of the following provides two-way communication

(A) Cellphone
(B) Pager
(C) Both (a) and (b)
(D) None of these

19. Which of the following is part of facsimile system

(A) Recorder
(B) Scanner
(C) Modem
(D) All of the above

20. Modems are used for ______

(A) Power supply
(B) Data transfer
(C) Both (a) and (b)
(D) None of these