Video Engineering Viva Questions



1. What do you know about TV?

The term "television" refers to the ability to observe things from distance. Its purpose is to extend the sense of sight, as well as the sound and scene being transmitted, beyond its regular limits.

2. Discuss the Use of Camera Tube?

For the video signal, the camera tube converts light input into electrical variations.

3. Describe Scanning?

Scanning is the conversion of the charge picture formed within the TV camera Tube into a variable electrical signal.

4. Discuss Horizontal Scanning and mention its Frequency Range.

The trace from left to right is deflected by an electron beam in a continuous uniform motion across the scene. 15625Hz is the frequency range.

5. Discuss Vertical Scanning?

While the electron beam is being deflected horizontally, the sawtooth current delivered to the vertical deflection coils moves the electron beam at a consistent pace from top to bottom of the grid.

6. Illustrate Flicker effect?

The television picture's scanning rate of 25 frames per second is insufficient to allow the brightness of one frame to flow seamlessly into the next. Flicker is the term for the contrast between bright and dark in a picture.

7. Discuss Interlaced Scanning?

The total number of lines is divided into 2 fields: odd and even. Each field is scanned in a process called interlaced scanning.

8. Discuss the use of Blanking Pulse?

Blanking pulses aim to hide the retraces that are necessary for scanning.

9. Describe Horizontal & Vertical Blanking Pulse?

• The horizontal retrace from right to left for each line is blanked out using horizontal blanking pulses.

• The vertical retrace from bottom to top for each field is blanked out using vertical blanking pulses.

10. What do you know about Synchronizing Pulses?

The synchronizing pulses are sent as part of the whole picture signal to the receiver, but they happen during the blanking period when no picture information is transmitted.

11. Discuss the use of Horizontal & Vertical Synchronizing Pulses?

• The start of horizontal retrace is determined by horizontal synchronization at the end of each line.

• The start of vertical retrace is determined by vertical synchronization after each field.

12. Define Aspect Ratio?

The aspect ratio refers to the width-to-height ratio of the picture frame.

13. Discuss the Average Brightness?

The average value of brightness variation of horizontal lines in a single frame is referred to as average brightness.

14. Explain Pedestal Height & DC Level?

• Pedestal height is the distance between average brightness and blanking level.

• The DC level is the distance between zero and average brightness.

15. List the TV Systems Used in Broadcasting?

The TV systems used in broadcasting are:

• FCC (Federal Communication Commission)

• NTSC (National Television Committee)

• CCIR (International Television Consultative Committee)

• PAL (Phase Alteration with Line)

• SECAM (Sequential Couleures A Memory)

16. Illustrate about Video Processing Unit?

To minimize the impacts of hum& noise, sync compression, and other distortions, the video signal input of 1 Vpp is processed in a stabilizing amplifier and sync regenerator.

17. Discuss Audio Processing Unit?

A high pass network with a time constant of 50μs applies a pre-emphasis to the audio signal. To get the signal up to standard levels, it is amplified.

18. Explain Diplexer?

It combines the visual and aural transmitters' outputs. It keeps the visual and auditory stimuli separate enough.

19. What do you know about Sound Trap Circuit?

To keep the signal out of the image, the video amplifier normally contains a trap circuit set to the intercarrier sound frequency of 5.5MHz. It separates the carrier signal from the sound signal.

20. How do you classify FM sound detectors?

The classification of FM sound detectors are:

• Foster Seeley discriminator

• Slope detector & Ratio detector

• Quadrature detector

Differential detector

• Phase-locked loop detector                              

21. What is the Purpose of a Color Camera?

Signal voltages corresponding to the intensity of each primary color light are produced with the help of a color camera.

22. Discuss Luminance Signal?

The luminance signal is recovered from the composite video stream using the luminance signal processing network.

23. What are the Benefits of using an LED Display?

The advantages of LED Display are:

• Lower power consumption

• More balanced color saturation

• Thinner & better contrast

• Brighter display & more reliable

24. What are the Benefits of Plasma Displays?

• Wider viewing angles and less visible motion blur

• Quick reaction time and high contrast ratio

25. State Plasma Displays' Disadvantages?

• Uses more power

• Doesn't operate at high altitudes

• Requires the use of a more expensive plasma suitable sensor

26. Describe Handy Cam? `

A handy cam is a compact camcorder that can be used with one hand. It is a combination of a camera and a tape recorder.

27. Discuss the Features of Handycam?

• Longer recording time

• 16-bit sound with greater fidelity

 • Editing and archiving are simple.

28. What do you know about CCTV?

CCTV is used in a wide range of applications, including education, industry, machine control, traffic management, and business.

29. What do you understand about Cable TV?

Cable television technology allows a large number of people to receive high-quality television transmissions. Hence subscribers that pay a price for this service will receive more TV programming.

30. Discuss Burst Blanking Circuit?

During color burst periods, the circuit blocks signal flow to the chrominance bandpass amplifier.

31. What is a Chrominance Band Pass Amplifier and how does it work?

The chrominance bandpass amplifier chooses the chrominance signal while eliminating unwanted signal components.

32. What is a Burst Amplifier and How Does It Work?

The color burst signal is separated from the chrominance signal, which is then amplified to the desired level by the burst gate amplifier. This transmission has a frequency of 4.43MHz.

Sreejith Hrishikesan

Sreejith Hrishikesan is a ME post graduate and has been worked as an Assistant Professor in Electronics Department in KMP College of Engineering, Ernakulam. For Assignments and Projects, Whatsapp on 8289838099.

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