Maharashtra State Board of Technical Education 2008 Diploma Electronics and Communication Communication System I - Question Paper

3 Hours / 100 Marks

Instructions - 1. All ques. are compulsory
2. Illustrate your answers with neat sketches wherever
necessary.
3. Use of Non-Programmable Electronic Pocket Calculator is
permissible.
4. Figures to the right indicate full marks.
5. presume suitable data, if necessary.


1. Attempt any 5 of the following: MARKS:20

a) Compare ranging from Woofer, Midrange and Tweeter kinds of speakers.
b) Explain the concept of interlace scanning in TV systems. Mention its advantages.
c) List the merits and demerits of negative modulation.
d) Explain the working principle of detection used in CD player.
e) Explain the working principle of LNA (Low Noise Amplifier) in cable television.
f) Explain the construction and working of Yagi-Uda Antenna.
g) Give the TV channel allocation of band-I and band-II

2. Attempt any 4 of the following: MARKS:16

a) List and discuss the functions of various controls available on Hi-Fi amplifier.
b) Draw construction diagram of PIL colour picture tube and discuss the basic principle used in it.
c) Explain Grassman’s legal regulations of additive colour mixture in colour TV systems.
d) Give horizontal sync pulse details in composite video signal.
e) Explain in brief a method of EHT generation in television system.
f) Compare Stereo and Hi-Fi amplifier.

3. a) Attempt the following: MARKS:8
Draw and discuss functioning of PAL-D decoder stepwise.

b) Attempt any 2 of the following: MARKS:8

1) State the function of subsequent blocks in B/W TV receiver.
1. RF timer
2. Video detector
3. Synchronizing circuit
4. IF amplifier
2) Define the subsequent terms related to TV systems.
1. Aspect ratio
2. Hue
3. Brightness
4. Saturation

3) State and discuss the concept of graphic equalizer.

4. a) Attempt any 1 of the following: MARKS:8

1) Draw the block diagram of satellite TV receiver and discuss its
working.
2) Draw the circuit diagram of chroma signal amplifier and discuss its working.

b) Attempt any 2 of the following: MARKS:8

1) Explain the advantages of fluorescent display system used in CD player.
2) Explain in brief the design concept for cable TV network.
3) List and discuss various components used for CD mechanism.

5. a) Attempt any 2 of the following: MARKS:8

1) Draw diagram of composite video signal. Show clearly horizontal sync pulses, peak white level, blanking level, pedestal height and dark level in diagram.
2) Draw only the block diagram of monochrome TV transmitter.
3) Draw and discuss the block diagram of Hi-Fi amplifier.

b) Attempt any 2 of the following: MARKS:8

1) State the functions of Cross-Over Network. Also draw the basic crossover network circuit and its response curve.
2) Write the values of subsequent standards for monochrome TV:
a) Aspect ratio
b) Channel bandwidth
c) Duration of horizontal line
d) Front porch
3) What is VSB transmission? Compare it with SSB and AM transmission.

6. Attempt any 4 of the following: MARKS:8

a) Draw the circuit diagram of push-pull power amplifier and discuss.
b) Give any 4 CCIR-B standards for colour signal transmission in PAL system.
c) Explain the need of Pre-emphasis and De-emphasis circuits in TV system.
d) Explain the properties of Dish Antenna.
e) Explain the basic principle used for camera picture tube.
f) Draw and discuss the block diagram of VCD player in brief.

Earning:   Approval pending.