Deemed University 2009 A.M.I.E.T.E Electronics & Communication Engineering Communication engineering – et (old scheme) - Question Paper

AMIETE – ET (OLD SCHEME)

Code: AE15 Subject: COMMUNICATION ENGINEERING
Time: three Hours Max. Marks: 100


NOTE: There are nine ques. in all.
· ques. one is compulsory and carries 20 marks. ans to Q. 1. must be written in the space given for it in the ans book supplied and nowhere else.
· Out of the remaining 8 ques. ans any 5 ques.. every ques. carries 16 marks.
· Any needed data not explicitly given, may be suitably presumed and said.

Q.1 select the accurate or the best option in the following: (210)

a. Unwanted energy, usually of random nature, current in a transmission system, due to any reason is called

(A) noise. (B) random signal.
(C) info. (D) carrier.

For a receiver of noise figure F operating at , K, the equivalent noise temperature is provided by

(A) . (B) .
(C) . (D) .

Modulation index of an AM wave with is

(A) 40%. (B) 80%.
(C) 125%. (D) 360V.

If there are (N an integer) equally likely and independent messages, then info bits in every message is

(A) . (B) .
(C) . (D) N.

The Hamming distance of an orthogonal code of k info bits is equal to

(A) . (B) .
(C) . (D) .

If sampling of 20 Hz bandwidth signals is at Nyquist rate using three bits per sample, then the bit rate (bits/s) is

(A) 17. (B) .
(C) 60. (D) 120.

The nonlinear device with kind characteristics used in a square-law AM demodulator is a

(A) diode. (B) capacitor.
(C) resistor. (D) comparator.

h. An amplitude-modulated signal, carrier plus double sideband is passed through a filter before transmission to the receiving end in the

Earning:   Approval pending.