Information & Communication technologies have taken a big leap forward and the distinction between broadcasting, telecommunications & multi-media services is disappearing very fast. Convergence is coming not only in technology but also in carriage infrastructure and receive equipment. Major driver of convergence is digital technology. Digital compression technology enables transmission of the same information by usage of less bandwidth in digital mode as compared to the requirement in analog mode. Digital technology is spectrum efficient and that has been a factor to promote digital revolution.
v Satellite services
Doordarshan is currently operating 31 TV channels. Satellite transmission of all these 31 channels is in digital mode. Digitalization of satellite channels has resulted in considerable saving in space segment capacity. In case of analog transmission, only one channel can be transmitted through a transponder whereas in case of digital transmission, five channels can be transmitted through a single transponder.
Doordarshan launched free to air DTH service “DD Direct Plus” in December, 04. DTH transmission is also in digital mode.
v Production centres
Digitalization of Production centres was a major thrust area of 10th Plan of Doordarshan. As part of 10th Plan, 17 major Doordashan studio centres have been fully digitalized. In addition, 30 smaller studio centres have been partially digitalized.
All the smaller Studio centres are planned to be fully digitalized during 11th Plan period besides digitalization of OB, ENG and Post Production facilities, subject to availability of requisite resources.
v Terrestrial transmission
Digital Television is the way of future, providing interference free reception and remarkable picture & sound quality. Digital Terrestrial Television (DTT) offers numerous advantageous over its analog counterpart viz. multi-channel operation; vastly superior and uniform reception quality; reception possible in moving vehicles; less power requirement. In addition, DTT is highly spectrum efficient.
DTT has been launched in certain countries viz. USA; UK & certain other European countries; Australia; Japan; China. Various countries have set cut off dates for complete switchover to DTT and switching off analog transmission.
India had selected DVB-T system for introduction of DTT in the country. To gain experience in DTT technology, Doordarshan had commissioned four digital transmitters one each at Delhi, Mumbai, Kolkata & Chennai in January, 2003, for an experimental service. Mobile TV service (DVB-H transmission) was started by Doordarshan in Delhi in May, 07. Digital transmitter set up at Delhi earlier in 2003 for experimental service was converted for carrying DVB-H signals.
It is a certainty that analog transmission will come to an end. Even though parallel technologies such as D-Cable, DTH, IPTV and Multimedia broadcasting would be prevailing, terrestrial transmission will have to continue on account of various reasons. Doordarshan, being the public service broadcaster will have to migrate to DTT in the years to come. Doordarshan plans to start digitalization of terrestrial network in 11th Plan and complete it by end of 12th Plan i.e. by 2017. In the scheme of digitalization of terrestrial network, cluster of certain LPTs are envisaged to be replaced by HPTs & also certain HPTs at new locations are planned to be set up.
Analog transmission will have to continue alongwith digital transmission for quite sometime. Cut off date for switching off analog transmission will have to be decided taking into account the percentage of population switching over to digital mode of reception. The policy of switchover to DTT would also affect citizens all over the country as it will require additional investment on part of TV homes for acquiring set top boxes in the initial years and subsequently in form of somewhat higher cost of TV sets.