VIDEO ENGINEERING VIVA QUESTIONS
VIDEO SYSTEMS
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.