The document provides an overview of television standards and systems, including the components and functioning of monochrome and color television, as well as the evolution towards high-definition television (HDTV). It details video signals, synchronization pulses, and the technical aspects of various TV technologies such as DLP, LCD, and plasma displays. The document also discusses different TV standards (NTSC, PAL, SECAM), as well as the historical development and impact of HDTV on broadcasting and consumer technology.

1. UNIT –II
TELEVISION STSNDARDS AND SYSTEMS

2. • Components of a TV system
• Interlacing
• Composite video signal
• Color TV
– Luminance and Chrominance Signal
– Monochrome and colour picture tubes
– Color picture tubes
– Color picture tv systems-NTSC ,PAL,SECAM
• Components of a TV Remote control and TV
camera tubes,HDTV,LED,LCD TV,DTH TV

3. Television
• To see at a distance
• Visual information in the scene is converted to an
electrical video signal for transmission to the receiver
• The image is reassembled on the fluorescent screen of
the picture tube
• In monochrome television ,the picture is reproduced
as shades of white , gray and black
• In color television the picture is reproduced in all their
natural colors as the combination of red green and
blue

5. Components of TV
• Picture Transmission
• Sound Transmission
• Picture reception

6. Components of TV

7. Monochrome TV
ONE ELECTRON GUN
CONTINUOUS PHOSPHOR COATING

9. Picture Transmission
Monochrome TV Transmitter

10. Picture transmission tool

11. Sound transmission

12. Picture reception

13. Interlacing

31. Monochrome TV Receiver

32. Elements of a Picture Tube

34. • Electron gun
• Control grid
• Accelerating grid
• Focusing grid

35. Cross sectional view about the neck of the
picture tube

36. Picture tube circuit and associated controls

38. Production of video
signal by
Photoemission
Production of video
signal by
Photoconduction

39. Cross sectional view of vidicon TV

40. Circuit for output signal

41. Leaky capacitor concept

45. Rear view of monochrome tv receiver

46. receiver

47. Function of a composite video signal

48. Sound signal Separation

49. Block diagram of AGC System

50. High voltage (EHT) Supply

51. Deflection circuit

53. Path of scanning beam in covering Picture
Area

54. Waveform of current in the horizontal
deflection coils
Produces Linear scanning in the horizontal direction

56. INTERLACING

57. COMPOSITE VIDEO SIGNAL
COLOUR TV PICTURE TUBE

58. Basics of composite video signal
• In TV Picture signal is a combinational of
multiple signals.
– Camera Signal : Corresponding to the variation of
light of given picture
– Synchronization Pulse : To Provide Synchronization
– Blanking Pulse : To make the retrace invisible

59. • In TV ,There are 625lines in one frame
– One frame – Divided into two fields 1 to 312.5
lines and 312.5 to 625 lines.
– Again 1st
field from 1to 312.5 divided into trace
292.5 lines (1 to 292.5) and retrace 20 lines(292.5
to 312.5)
– 2nd
field from 312.5 to 625 lines again divided into
trace(292.5 lines(312.5 to 605 lines)retrace 20
lines (605 to 325lines)

60. Composite video signal
RANGE OF VIDEO SIGNAL
V/VMAX = PERCENTAGE OF SIGNAL
SYNCHRONIZATION

64. Camera Signal
• Lowest Amplitude at 12.5 % shows whitest
part of the picture.
• Highest amplitude at 75% shows darkest part
of the picture.
• Signal transmission : Negative Polarity
transmission

65. Horizontal blanking Pulse
• Horizontal blanking pulse (12µs) has three
portion
– Front Porch (1.5 µs) Fly black initiated with black
level
– Horizontal synchronization pulse (4.7µs)
• Synchronization is done to Tx and Rx by Pulse
– Back Porch (5.8 µs)
• Fly back completed with black level.

67. HORIZONTAL BLANKING

69. HORIZONTAL BLANKING

70. BACK PORCH

71. TRACE and RETRACE

73. Vertical Synchronization Pulse
• It is of 2.5 line duration
• So it’s time period is 2.5 * 64 =160 µs
• At the end of first field vertical sync pulse is
added at (312.5 to 315 lines)(2.5 lines)
• At the end of second field vertical sync pulse is
added at (1 to 2.5 lines)
• One vertical sync pulse ends at half line period
and one ends at full line period.

74. Vertical sync pulse 75% to 100 %

75. Vertical Blanking period
• It is the period during which picture
information is completely suppressed
and flyback retrace of field is initiated and
completed.
• Its of 20 lines duration .so its time period is
20 * 64 µs = 1.28 ms

76. COLOUR TV PICTURE TUBE
• Basics
• Diagram of Picture tube
• Components
• Working
• Generation

77. Basics of colour TV Picture Tube
• The receiver of Colour TV receives Y, B-Y, R-Y
video signals
• Y is Luminance signal Y= 0.3R+0.59G+0.11B
• B-Y,R-Y is having information regarding colours
• At the receiver of colour TV ,In delta
gun ,Three guns are placed at 120 degree with
each other

78. ANY COLOUR CAN BE MADE USING RED,GREEN & BLUE

79. • The tube having a screen where three colour
phosphor dots are arranged in groups known
as triads.
•

80. • Three colour beam passes through single hole of a
shadow mask
• On dot triads screen, three dots at the same time
• Distance between shadow mask and dot triads is 1cm
• Triads are repeated and depending upon the size of
the picture tube approx 1 million such dots forms
3.33 lac triads, triads are deposited on the glass tube.
• About 1 cm behind screen perforated metal sheet
known as the shadow mask

81. • The mask has one hole for every phosphor dot
triad on the screen
• Ratio of electron passing through the shadow
mask is 20 %. Other 80% electrons are
dissipated as heat.

82. Three signals are forwarded to colour TV
• Y
• B-Y
• R-Y

83. Diagram of Colour TV Picture Tube

84. • V’K2 –VK = (VR –VY )- (- VY) = VR
• V’K2 –VK = (VG –VY )- (- VY) = VG
• V’K3 –VK = (VB –VY )- (- VY) = VB

86. TV STANDARDS
HDTV

87. NTSC COLOUR
• National Television Systems Committee
• Developed in US
• Compatible with Monochrome Receiver
• Consists of
– Luminance signal Y
– Chrominance Signal
Field rate: 60 Hz
Line rate:15750 Hz
526 Lines

88. NTSC Colour system

89. YIQ (NTSC)
• YIQ from RGB
Y = .299R + .587G + .114B
I = .74 (R - Y) - .27 (B - Y)
Q = 0.48 (R - Y) + 0.41 (B - Y) YIQ with Y=0.5

90. PAL
• Phase Alternation by line
• Developed in Germany
• 625 lines

91. Generation of PAL system

92. Color Space: YUV
• PAL video standard
– Y is luminance
– UV are chrominance
• YUV from RGB
Y = .299R + .587G + .114B
U = 0.492 (B - Y)
V = 0.877 (R - Y)
U-V plane at Y=0.5
Y
U
V

93. Video Representation

94. HDTV
To Overcome Limitations of Analog Television
• Noise free pictures
• Higher resolution images Widescreen / HDTV
• No Ghosting
• Enhanced Sound Services
• Other Data services.

95. • HDTV is generally recognized as a digital video
broadcast with a minimum resolution of 1280
pixels wide and 720 pixels high, a rate of 30 or
more frames/second and usually an aspect
ratio of 16:9.

96. HDTV History
• Early 1980’s: – Japan created analog HDTV
• Mid-1980s:
– US, trying to stay competitive, decided to go
digital
– Congress gave stations a separate channel for
transition to digital broadcast with the goal of all
stations using digital broadcasts by 2006.

97. • Less than 15% of US homes have HDTV
capabilities
• Approximately 21% of stations have digital
broadcasts

98. • A standard definition analog television uses a cathode ray
tube with an electron gun to guide the path of an
electron beam to “paint” 480 vertical lines across the face
of the screen. Each time the beam strikes a dot of
phosphor, light is produced. For a color television set,
each spot consists of a group of three phosphor
elements; one for each primary color.

99. How HD Works

100. Implementation in technologies
• Plasma – Like LCD monitors, plasma HDTV sets are thin and are made up of
cells that correspond to pixels sandwiched between glass plates. Plasma
cells contain three separate gas-fill sub-cells, one for each color. When a
current is applied to a sub-cell, it ionizes the gas emitting ultraviolet light.
The ultraviolet light in turn excites fluorescent substances in the sub-cells
that emit red, blue or green light.
• DLP – Digital light processing is a technology used in projection displays. In
DLP monitors, light is reflected off an array of microscopic hinged mirrors.
Each tiny mirror corresponds to a visible pixel. The light is channeled through
a lens onto the surface of the screen. Single chip DLP projectors can display
16.7 million colors. 3- chip projectors can display 35 trillion colors.
• LCoS – Similar to DLP, LCoS projection systems use liquid crystals instead of
mirrors to block light. The liquid crystals are arranged in a grid in front of a
highly reflective surface.

101. HD TV Screen Refresh Rates
• A rate of 24 frames/second (progressive) has
been the movie film standard since the mid-
20’s
• The television industry has used a rate of 60
frames/second (interlaced) since the 40’s
• Newer HDTV’s are being marketed as 120 Hz
and 240 Hz using circuitry to help reduce
motion blur

102. Technical Aspects

103. Frame rate conversion - 3-2 pulldown

104. What is a format
• Number of active pixels per line
• Number of active lines per frame
• Scanning mode
• Picture aspect ratio
• Frame rate
Two main Standards are
• SMPTE 274 M
• SMPTE 296 M

105. Archiving High Definition
• Standard definition
video
– 720 pixels 576 lines
– 1- hour programme
file size : 72 GB
• High definition
video
• 1980 pixels 1080
lines
• 1- hour
programme file
size : from374
GB to 673 GB*

106. • Judging simply on pixel count, a 1080i HDTV
image is 6 - 9 times better than a standard,
NTSC image
• Audio is also improved

107. HDTV & SDTV Comparison

108. Advantages
• By using lower-definition signals, one channel
can be split into several channels
• Extra channels used for:
– information services (data casting)
– music
– Internet services

109. HDTV Features
• Provides up to 60 frames/sec screen writing
• Uses MPEG-2 data compression
– source info data rate is 1.2Gbps
– broadcast data rate is 20Mbps
• Square pixels 1/4 the size of analog TV’s pixels

110. Types of HDTV

111. Connecting To Analog TV

112. Connecting To Digital TV

113. Impact of HDTV
• Broadcasters & consumers spend more $
• Increased visual clarity has forced designers
to spend considerably more money on sets,
set dressings
• Blu-Ray vs HD-DVD

114. Camera Tubes types
• Image Orthicon,
• Vidicon,
• Plumbicon.

115. Camera Tubes
• A TV camera tube may be called the eye of a TV
system.
Some of the more important functions must be,
(i) Sensitivity to visible light,
(ii) Wide dynamic range with respect to light
intensity, and
(iii)ability to resolve details while viewing a
multi-element scene.

116. THANK YOU