Download Television and Video Engineering

TELEVISION AND VIDEO ENGINEERING
QUESTION BANK
UNIT-1
PART-A
1. What is scanning?
2. Give reasons why we prefer negative transmission.
3. What is vestigial sideband transmission and why it is used for transmission of TV
Picture signal?
4. Why are blanking pulses not used as synchronous pulses?
5. Define Aspect Ratio.
6. What is the purpose of blanking pulses?
7. Define Vertical Scanning.
8. Define total channel bandwidth using vestigial lower band width.
9. What specifications of TV system decide horizontal and vertical resolution?
10. Draw the vestigial side band characteristics of TV transmitter and receiver.
11. What is the significance of choosing the number of lines as 625 as not as 623 or
627 as the frame reception rate as 25 and not 24 as in motion pictures.
12. Why is the portion of lower side band of the AM signal transmitted along with
the carrier and full VSB?
13. What is Flicker? How it can be eliminated.
14. What are serrated pulses?
15. What is equalizing pulses?
16. What is meant by Pedestal?
17. What do you meant by interlaced scanning?
18. What is vertical and horizontal resolution?
19. What are the characteristics of camera tube?
20. What is the composite video signal?
21. What are the factors that affect bandwidth of a channel?
22. What is the use of front porch?
23. Define Resolution.
24. What is Gamma of the picture?
25. What do meant by dark current?
PART-B
1. Derive an expression for the bandwidth of a video signal in terms of number of
Lines and field frequency.
2. Describe the interlaced scanning to avoid flicker in TV receiver.
3. Discuss the Merits and Demerits of positive and negative amplitude modulations
4. Draw the cross-sectional view of an Image orthicon camera tube and explain how
it develops video signal.
5. Justify the need for pre and post equalizing pulses.
6. Show the elements of a picture tube employing electrostatic focussing and
Magnetic deflection. Explain the functions of brightness and contrast color
Circuits.
7. Explain the Working of TV picture tubes. Explain the composite video signal.
8. Briefly describe the operational principle of a camera tube of Vidicon format.
9. What is interlaced Scanning? How does it helps in removing the undesirable
Flickering effects.
10. Explain the sound signal transmission.
11. Explain in detail about the composite video signal.
UNIT-2
PART-A
1. What are the main sections of video IF sub-system.
2. Define image rejection Ratio.
3. Where and how is the inter carrier sound signal separated from the video signal.
4. What is the function of a reflector and a director in a yagi antenna.
5. What are the merits of negative transmission?
6. What are inter carrier- sound receivers.
7. Differentiate Co-channel interference and adjacent channel interference.
8. What is EHT and why is it required?
9. A ghost image is produced 2 cm to the right of main image in a 40 cm wide
Picture tube. What is the difference in the path length of the direct and
Reflected rays?
10. Draw the construction of a folded dipole and state its function.
11. What is the purpose of an AGC circuit in a TV receiver?
12. What is the principle of inter carrier sound system.
13. Mention the reason for DC reinsertion in a TV receiver.
14. What is the principle of AGC?
15. What are the factors that influence the choice of IF?
16. What is keyed AGC?
17. What do you understand by partial DC coupling.
18. What causes trailing and leading ghost images?
19. What is Balun?
20. What is the use of HOLD control.
21. What is ghost image?
22. Write the use of AFC circuits in the receiver?
23. What are Trap circuits?
24. Define directivity of antenna.
25. Define antenna gain.
PART-B
1. Explain the working of silicon diode array Vidicon camera tube.
2. With the neat block diagram explain the features of a monochrome television
Receiver?
3. what are the constituents of composite video signal and explain their uses?
4. Explain the vestigial sideband transmission.
5. Explain the constructional details of a turnstile antenna and its suitability for
television transmission.
6. Describe with a block diagram the working principle of UHF tuner.
7. Describe how EHT is developed from the horizontal output circuit of the sweep
amplifier.
8. Discuss on the factors that influenced the choice of picture IF and sound IF in the
625B monochrome television system.
9. Explain the working of a television transmitter antenna and a television receiver
antenna.
10. Why is AM preferred for picture signal transmission.
11. Explain the working of automatic gain control circit and automatic freq uency
control circuit.
12. Explain the factors which influence the choice of intermediate frequencies in TV
receivers.
13. Draw the block diagram of a monochrome television receiver and explain each
block in detail.
14. Explain DC Re-insertion. and Receiver Antennas.
UNIT-3
PART-A
1.
2.
3.
4.
5.
6.
7.
What is Gamma of the picture?
Define Hue and saturation.
What do you understand by degaussing and why is it necessary?
Define purity and convergence.
Write down the transmitter matrix with reference to color television system.
Define compatibility and Reverse compatibility
Schematically illustrate the formation of the chroma signal for a color bar
pattern after the color difference signals have been scaled down in
accordance with corresponding weighting factors.
8. What is additive mixing?
9. What is color burst?
10. What are weighing factors?
11. What is pincushion distortion? How it can be corrected.
12. Why is the color signal bandwidth requirement much less than that of they
signals?
13. What do you understand by degaussing?
14. What are the types of mixing available?
15. Define compatibility with respect to TV receivers.
16. What are the draw backs of delta-gun tube?
17. Why is the color signal bandwidth much less than that of Y signals?
18. Define compatibility with respect to TV transmission?
19. Why Trinitron color picture tube is superior to delta-gun and P.I.L picture?
20. What are the weighing factors used for (R-Y) and (B-Y) signals?
21. Why is it necessary to connect a very high voltage at the final anode of a
color picture tube?
22. What is frequency interlacing?
23. What do you understand by grey scale tracking?
24. Define chrominanace?
25. Define luminance signal?
26. Draw the simplified circuit of a booster amplifier.
27. Draw the diagram of any two trap circuits used in video IF amplifier
PART-B
1. Discuss the factors which influence the choice of intermediate frequencies in
TV receivers.
2. Write the need and working of automatic gain control circuit of a
monochrome TV receiver.
3. Illustrate the features of TV receiver antenna and VHF tuners.
4. Explain in detail the intercarrier sound section of a monochrome receiver.
5. Explain the sequence of operations involved in achieving the luminance and
chrominance signals from the outputs of the camera tube.
6. Describe the constructional details of a P.I.L tube and explain its
distinguishing features.
7. Explain how by frequency interleaving the colr information is accomdated
within the same channel bandwidth of 7MHz.
8. Explain how the grey scale tracking is carried out both for low and high
lights of the video signal.
9. Explain the working of a color television picture tube.
10. Write notes on NTSC, PAL and SECAM system.
11. With necessary diagram explain the delta-gun color picture tube.describe
how purity and convergence are achieved in it.
12. Explain the following: a) Pincushion correction techniques.
b) Explain the color signal Transmission.
UNIT-4
PART-A
1. What are complementary colors? How do you find the complement of a
particular primary?
2. Why are different bandwidth assigned to Q and I signals in the NTSC
system?
3. Why is the color burst signal transmitted after each scanning line in the PAL
system?
4. State the advantages of PAL color system over NTSC color system?
5. What is the purpose of color killer circuit?
6. State the limitations of NTSC system.
7. What is the function of the color killer circuit?
8. What are the Basic differences between SECAM?
9. What is the need for delay line in the path of Y signal?
10. What is the color killer?
11. What is the use of IDENT pulse?
12. What is the use of ACC amplifier?
13. Why we have to reweigh the u and v demodulated signal?
14. What are the main functions of color decoder?
15. State the merits of RGB matrix in B pal-d receiver?
16. Draw the block diagram of the circuit that separates U and V color signals?
17. What is the basic difference between SECAM and other color TV system?
18. What is IDENT signal and how it is separated in the receiver?
19. Why are modulated sub carrier vectors shifted by 33 degrees to constitute Q
and I signals in the NTSC systems?
20. Mention the use of comb filter in pal-d receiver?
21. Justify the choice of 3.579545 MHz as the sub carrier frequency in the NTSC
system?
22. Why is the color burst signal transmitted after each scanning line and why
pal color burst is often called the sampling burst?
23. How is reweighing done in the matrixing circuit?
24. List the Merits and Demerits of SECAM system?
25. Why we have to reweigh the U and V demodulated signal?
PART-B
1. Draw neatly the block diagram of a SECAM receiver and explain?
2. Describe color signal processing in PAL receiver and list down the merits
and Demerits.
3. Explain the encoding process in the PAL color system.
4. Describe the encoding and decoding process of SECAM system.
5. Explain the delay line method of separating U and V signals in a PAL
receiver?
6. Explain in detail, the color signal processing as done in PAL-D receivers.
7. Explain the sub carrier generation and control circuits used in PAL-D
receivers.
8. Draw the simplified block diagram of the NTSC color receiver and explain
each block.
9. Explain the sequence of modulation in the PAL color system and illustrate
the color burst swing in PAL system.
10. Describe the following:
a) Separation of U and V signal.
b) I dent and color killer circuits
c) Merits and Demerits of SECAM system?
UNIT-5
PART-A
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What is Vectroscope?
What is extended coverage of TV?
How does a high definition TV differ from a conventional TV?
What are the different methods of transmitting 3-D signals over
communication lines?
What is TV booster?
What is a high definition TV?
What is Tele Text?
Name the various digital equipments required in TV studio.
9. Explain helical scanning in video tape recorder.
10. Draw the block diagram of the PLL used in frequency synthesized tuners.
11. What limits the life of a satellite once put in an orbit?
12. What are Transponders?
13. What is the Transponders as used in satellite?
14. What is bullet amplifier?
15. What is Front-end converter?
16. What is meant by scrambling of TV signals?
17. What are the methods available to scramble TV signals?
18. What is Descrambler?
19. Why is the helical scan method of video recording preferred in VCRs?
20. What is camcorder?
21. How is camcorder differing from a VCR?
22. How is a DVD different from CD?
23. What do you mean by character rounding?
24. How much information in terms of letters or characters is contained in each
page?
26. Which line numbers of the picture field are chosen for tale text service and
why they are preferred?
PART-B
1. Discuss the basic principles of remote control system.
2. Write short notes on a) Cable Television
b) Closed circuit TV.
3. Discuss briefly on a) Satellite Television.
b) Digital TV
4. Discuss briefly on 3D TV Television.
5. Discuss briefly on Videodisc system.
6. Discuss briefly on ED TV Television.
7. Describe about VCR in detail with suitable Diagram.
8. Explain the elements of Digital TV System.
9. Describe the basic distribution system for CATV network.
10. Explain the simplified block diagram of the earth station receiver for
recovering base band video and audio signal.
11. With block diagram explain the working of Video tape recorder.