Television Broadcasting

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Television Broadcasting

• 259109 Telecommunication in Thailand
• Assist.Prof.Tharadol Komolmis
• Department of Electrical Engineering
• Faculty of Engineering
• Chiang Mai University

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Television Broadcasting

• Simplex (one-way communication)
• Point to- Multipoint
• Picture and sound Communication(Moving picture
  or video)
• Need modulation with carrier
• Amplitude modulation AM
• Sound modulated with sub carrier (AM or FM)

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Television broadcasting

• Audio Bandwidth
• 15 kHz base band
• Video Bandwidth
• 4-5 MHz base band
• Channel Bandwidth (between carrier)
• 7-8 MHz

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Television broadcasting

• Video signal (black white or luminance)
• 525/60
• 525 Horizontal line/frame, 30 frame/sec
• 4.2 MHz bandwidth
• 625/50
• 625 Horizontal line/frame, 25 frame/sec
• 5 MHz bandwidth

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Color signal

• Primary color
• Red
• Green
• Blue
• Complementary color
• Cyan
• Magenta
• Yellow

Blue
Red
Magenta
Yellow
Cyan
Green
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Television broadcasting

• Color signal (Chrominance)
• Contain color information
• Composite Video composed of
• Luminance information
• Chrominance information
• Synchronize information

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Color System

• PAL
• stands for Phase Alternation Lines
• 625 lines
• offers more picture detail and wider bandwidth.
• PAL has been adopted by almost all 50 Hz
  countries in the world.

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Color System

• NTSC
• stands for National Television Standard
  Committee
• which established the American TV broadcast
• 525 lines
• The NTSC system has higher frame rate (60 Hz30
  frame/s) which reduces visible flicker and
  picture noise.

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Color System

• SECAM
• stands for SEquential Couleur Avec Memoire
• used in France and many eastern European
  countries.
• 625 lines and offers good picture detail and
  stable hues

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TV Color System broadcasting

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Color System use in Thailand

• PAL
• Horizontal lines 625 lines
• Frame rate 25 frame/sec
• Color subcarrier 4.43 MHz
• Video bandwidth 5 MHz
• Audio subcarrier 5.5 MHz
• Audio modulation FM
• Channel Bandwidth
• PAL-B (use in VHF band) 7 MHz
• PAL-G (use in UHF band) 8 MHz

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Color System use in Thailand

• PAL spectrum

Main(RF) carrier
sound subcarrier
color subcarrier
frequency (MHz)
5
5.5
4.43
1.25 MHz
7 MHz
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Television Broadcasting

• Transmitting Antenna
• Dipole array (super gain)
• Horizontal Polarization
• Receiving Antenna
• Yagi array for outdoor
• Dipole for indoor

Yagi array
Horizontal Polarization
Vertical Polarization
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Television Broadcasting in Thailand

• 24 June 2498 Thai TV Ch.4 (525/60 blackwhite)
• 25 Jan 2501 Army TV Ch.7 (525/60 blackwhite)
• 27 Nov 2510 Army TV Ch.7 color (625/50 PAL-B)
• 26 Mar 2513 Thai TV Ch.3 color (625/50 PAL-B)
• 2517
• Thai TV Ch.4 blackwhite change to Thai TV
  Ch.9 color
• Army TV Ch.7 blackwhite change to Army TV
  Ch.5 color
• 1 Nov 2531 Thai TV Ch.11
• 2537 ITV (UHF)
• 2548-2550 Thai TV Ch.3 VHF change to UHF
• 2550 ITV change to ThaiPBS
• TV Channel 11 change to NBT

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Television Broadcasting in Thailand

• Frequency allocation
• VHF-Low TV Ch.No.2-4 (47-68MHz)
• FM Radio broadcasting (88-108 MHz)
• VHF-High TV Ch.No.5-12 (174-230 MHz)
• UHF TV Ch.No.26-60(510-790 MHz)

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Television Broadcasting in Thailand

• In each area use different Channel Number
• For example in Chiangmai city area
• ThaiTV3 UHF Ch.No.46 (670-678 MHz)
• TV5 VHF Ch.No.5 (174-181 MHz)
• BBTV Ch7 VHF Ch.No.7 (188-195 MHz)
• Modern9 VHF Ch.No.9 (202-209 MHz)
• NBT VHF Ch.No.11 (216-223 MHz)
• ThaiPBS UHF Ch.No.34 (574-582 MHz)

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Example of Channel Allocation
ThaiTV3 TV5 BBTV Ch7 Modern9 NBT Thai PBS
Chiangmai City 46 5 7 9 11 34
Fang, Chiangmai - - - - 32 29
Chiangrai 8 12 6 4 10 27
Phayao - 44 - - 10 34
Phrae 6 4 2 10 8 34
Nan 7 5 - 9 11 27
Tak 6 4 8 10 12 34
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Television Broadcasting in Thailand
Chiangrai Ch.No.27
Fang Ch.No.29
Chiangmai Ch.No.34
ThaiPBS
Lampang Ch.No.29
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Master Antenna Television MATV

• For multiple televisions to share the same
  antenna
• The system to distribute video signal to multiple
  points
• Need devices to divide signal
• Splitter divide total input signal equally
• Tap-off divide part of input signal
• Amplifier for large system
• Cable

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MATV Devices in MATV system

• Splitter divide total input signal equally
• 2-way Splitter 4-way Splitter

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MATV Devices in MATV system

• Tap-off divide part of input signal (most signal
  pass through)
• 1-way 2-way 4-way Tap-off

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MATV Devices in MATV system

• Amplifier some values need to be considered are
• Gain
• Output level
• Noise Figure

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MATV Devices in MATV system

• Cable used in MATV is coaxial cable with
  characteristic impedance 75 ?
• RG-6/U RG-11/U

Loss
Loss
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MATV Examples

• 2 points 4 points

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MATV Examples

• 12 points 24 points

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