INTRODUCTION LARGEST BOARDCASTING ORGANISATION 1ST SERVICE STARTED ON 15TH SEP,1959 Doordarshan = Distant + Show. Doordarshan is an Indian public service broadcaster. One of the largest broadcasting organizations in India in terms of the infrastructure of studios and transmitters.
Terrestrial television in India started in Delhi on 15 September 1959. The regular daily transmission started in 1965 as a part of All India Radio. Television services were separated from radio in 1976. In 1982 color TV was introduced in the Indian market.
TELEVISION STANDARDS• NTSC-National television standards committee(US) (525 Horizontal & 60 vertical lines)• SECAM-System electronics for colour avec memorie(FRANCE)(625 vertical & 50horizantal lines)• PAL- Phase Alternating lines(GERMANY)(625 horizontal & 50 vertical line)Television standards used in India is PAL
PAL ENCODER & DECODER• Input is the primary colour (i.e. red, green, blue) into matrix circuit as Y, R- Y, B-Y.• Y=0.30R+0.59G+.11B• U=0.477(R-Y)• V=0.895(B-Y)• Out of 625 horizontal line only 575 are active• 50 vertical lines
• Front portch is to crate horizontal blankingAlso contain sync pulse• Back porch is the portion of each scan line between end of horizontal sync pulse and start of active video signal• Colour burst is absent in the black and white transmission of video signal
TELEVISION COMMUNICATIONSYSTEM CRYSTAL POWER OSCILLATOR RF AMPLIFIER AMPLIFIER COMBINING SCANNING CIRCUIT NETWORK DEPLEXER CAME AM VIDEO RA MODULATION AMPLIFIER AMPLIFIER AUDIO FM SOUNDMIC. FM MODULATOR AMPLIFIER TRANSMITTER
TELEVISION STUDIO A television studio is an installation in which television or video productions take place .
COMPONENTS OF TV STUDIO• ACTION AREA• PRODUCTION CONTROL ROOM• MASTER SWITCHING ROOM• CONTROL APPARATUS ROOM• CHARACTER GENERATOR• VIDEO TAPE RECORDING• EARTH STATION• TRANSMITTER
ACTION AREA TALK BACK MANA GEMEN T LIGHTN ING UNITS AUDIO CONNE CTERCAMERAHEADUNIT
PRODUCTION CONTROL ROOM• MONITOR PROGRAM AND GRAPHICS• VISION MIXER (to select video sources)• Audio console• Add video effect
MASTER CONTROL ROOMIt connect the of following equipment• Camera control unit• VTRs• Patch panel• Vision mixer
• CHARCTER GENERATORSNames and graphics inserted into programs• CONTROL APPARATUS ROOMIncludes the power supply unitUPS roomGenerator• VIDEO TAPE RECORDERConsists of recorded materials i.e. v.c.r
Component of earthEARTH STATION station Earth Station is a very important part of satellite • PDA (Parabolic communication system for Dish Antenna) broadcasting of signals. • FEED It is an uplink center from • Wave Guide / Low which the signals are fed to Satellite for distribution in a Loss Cable specified area covered by • HPA the Satellite. (TWTA, Klystrons) The signal is up-linked • Up converter from the Earth Station and received by many down • Modulator link centers in TV broad • Encoder casting via PDA(Personal • Multiplexer Digital Assistant). • IRD (Integrated Digital Earth Stations are widely used because of Receiver Decoder various advantages over analog.
TRANSMITTER Aid of antenna Produces radio wave Connect earth station to satellites Also connect television
ANTENNA & SATELLITE• An antenna (or aerial) is a transducer designed to transmit or receive electromagnetic waves. In other words, antennas convert electromagnetic waves into electrical currents and vice versa.
TYPES OF ANTENNA • Isotropic antenna (idealized) o Radiates power equally in all directions • Dipole antennas o Half-wave dipole antenna (or Hertz antenna) o Quarter-wave vertical antenna (or Marconi antenna) • Parabolic Dish / Reflective Antenna