Code: A-20
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 TEom modes of a circular waveguide have a unique characteristic in that the attenuation of these fields continues to
 

(A) increase at higher frequencies.
(B) decrease at higher frequencies.
(C) constant over the operating band.
(D) decrease at lower part of frequency based and then increases.
b. A Smith chart is used
 

(A) To calculate Current. Voltage.
(C) To calculate Power.

(B) To calculate
(D) To calculate Impedance.
c.

A Dominant mode in a rectangular wave guide is a

 

(A Non propagating mode.
(B) A propagating mode with lowest cut off frequency.
(C) Propagating mode with circular polarization.
(D) Hybrid mode.
d. A Microstrip is formed by
 

(A) One conductor between two ground planes and dielectric.
(B) One conductor and one ground plane and dielectric.
(C) One conductor surrounded by a circular ground plane and dielectric.
(D) Two conductors with one ground plane and dielectric.
e. A matched termination is a
  (A) A tapered Capacitive load
(C) A tapered Resistive load.
 (B) A tapered Inductive load.
(D) Tuned circuit load.

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