Code: A-21
Time: 3 Hours
Subject: DIGITAL COMMUNICATIONS
Max. Marks: 100

NOTE: There are 11 Questions in all.

  • Question 1 is compulsory and carries 16 marks. Answer to Q. 1. must be written in the space provided for it in the answer book supplied and nowhere else.

  • Answer any THREE Questions each from Part I and Part II. Each of these questions carries 14 marks.

  • Any required data not explicitly given, may be suitably assumed and stated.

Q.1       Choose the correct or best alternative in the following: (2x8)

a. The Nyquist rate of sampling for the signal
 

(A) 200.
(C) 300.

(B) 400.
(D) 250.
b. The channel capacity of a 5 KHz bandwidth binary system is
 

(A) 10,000 bits / sec.
(C) 8000 bits / sec

(B) 5000 bits / sec.
(D) 4000 bits / sec.
c.

One type of special self checking error code is

 

(A ARQ (exact count) code.
(C) Convolutional code.

(B) BCH code.
(D) Cyclic code.
d. The CRC circuit is basically a
 

(A) Decoder circuit.
(C) Shift register circuit.

(B) Multiplexer circuit.
(D) Adder circuit.
e. The modulation method that represents bits as different phase shifts of a carrier is known as
 

(A) ASK.
(C) PSK.

(B) FSK.
(D) MSK.
f. The type of modulation used with direct sequence spread spectrum is usually
  (A) PSK.
(C) FSK.
(B) ASK.
(D) MSK.

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