04-02-2013, 03:07 PM
Training at Doordarshan kochi
Training at Doordarshan.pptx (Size: 203.93 KB / Downloads: 67)
History
A Public Service Broadcaster
largest terrestrial television network in the world
Service started in New Delhi on 15 September 1959
Regular daily transmission started in 1965
National telecasts were introduced in 1982
Doordarshan in Kerala
Number of studios : 3
Transmitters can high power transmitter or low power transmitters.
HPT : vision and sound carriers can be generated, modulated and amplified separately , combined in the diplexer at the transmitter output.
LPT sound and vision are modulated separately but amplified jointly
DD cochin-HPT
HPT-7
LPT-22
Studio
Origin of a programme
Programme are live or recorded or from OB spot
Programmes from studio to transmitting centre through broadcast quality telephone lines or studio transmitter microwave/VHF links
Size 20mx20mx8.5m
Requirements
Camera
Audio system
Lights
Key light
Fill light
Back light
Audio Video connector
Flooring: marblex is provided
Walls:Ivory finished celotex surface
Cyclorama: to avoid unnecessary reflections
Air condition,Safety measures etc..
TV Transmission
Audio signal
Acoustic vibration converts to signal by lapel or condensor microhone.
Frequency modulation and line of sight propogation
Audio carrier frequency : 229.75MHz
Video signal
Light converts to electrical signal by charge coupled device.
AM and ground wave propogation
Video carrier frequency : 224.25MHz
VESTIGIAL SIDE BAND TRANSMISSION
Normal amplitude modulation require 11 MHz bandwidth
limit the number of channels in the spectrum allotted for TV
Part of lower side band +upper side band=5.75 MHz
CONCLUSION
Doordarshan is a Public Service Broadcaster and among the largest terrestrial television network in the world. Doordarshan cochin is a high power transmitter.It mainly receives the programmes from Delhi and Trivandrum through satellite INSAT 3A&4B, Mainly DD cochin broadcast DD1 and DD news.The two types of transmitters that are in use are Rohde and Schwarz which is for DD1 and NEC for DD news.The antenna here is a dipole antenna and total number of antenna is 32.