Yashwantrao Chavan Maharashtra Open University 2006 Certification TES Communication Engineering - II - Question Paper

TES072/EE/20070814
Communication Engineering - II
Time : 180 minutes Marks : 100
Instructions for the students :
1. All ques. are compulsory.
2. “Long ans kind ques. (LAQ)” is a supply kind ques. of 20 marks,
which require typical ans of about 60-80 lines in about 32-40 minutes.
3. “Short ans kind ques. (SAQ)” is a supply kind ques. of five marks,
which require typical ans of about 15-20 lines in about 08-10 minutes.
4. Use of non-programmable kind of scientific calculator is allowed.
5. Draw neat diagrams wherever necessary.
6. presume suitable data if necessary.


Long ans kind ques. (LAQ’s)
1. (a) discuss what is meant by the SWR on a line. What is its
value when a line is perfectly matched and establish its
relation with reflection coefficient.
(b) define the ionoshperic propagation system with a suitable
diagram and compare it with ground wave propagation.


2. (a) discuss the term radiation pattern, gain and directivity,
beamwidth, front-to-back ratio, major and minor lobes as
antenna characteristics.
(b) A helical antenna with 6 turns is to be constructed for
frequency of 1.5 GHzi)
compute the optimum diameter and spacing for the
antenna and obtain the total length of the antenna.
ii) compute the antenna gain in dBi.
iii) compute the beamwidth.


3. (a) discuss the working of pulse radar. discuss any application
of his radar.
(b) discuss circulators and isolators.


4 (a) define MMDS and LMDS.
(b) discuss with a suitable block diagram C-band transponder.


Short ans kind ques. (SAQ’s)
5. A generator sends 100 mW down a 50 ohm line. The generator
is matched to the line, but the load is not. If the coefficient of
reflection is 0.5, bow much power is reflacted and how much is
dissipated in the load ?

6. define parabolic reflector. 5
7. discuss with a suitable diagram, the Klystrons tube. 5
8. A satellite transmitter operates at four GHz with a transmitter
power of 7W and an antenna gain of 40 dBi. The receiver has an
antenna gain of 30 dBi, and the path length is 40,000 km,
compute the signal strength at the receiver

Earning:   Approval pending.