This is so as digital recording is made using a high quality technique which breaks down the signals into thousands of very small signals represented in an exact form unlike analog transmission.

The decision by the government to digitise Doordarshan broadcasts will thus not only improve picture quality but also promise a great boost for advertisement revenues.

In fact the communications sector itself is set to undergo a revolution with digital terrestrial television broadcasting (DTTB) replacing the existing analog system which uses outdated technology, according to BK De, chief engineer, Doordarshan.

But what is digital television broadcasting and what implications does it have for communications? Simply put, in the current analog system separatetransponders are required for transmission on each channel, while in the case of digital transmission, the signals are compressed into a single transponder.

While this is one of the fringe benefits of using a digital transmission signal as opposed to the conventional analog system there are numerous other advantages accruing from switching over to the new system.

Digitising of broadcasts has the advantage that it compresses signals into very few frequencies, unlike analog transmission which is spaced out over a broader spectrum.

AK Guin, a senior official in the research and development wing of All India Radio and Doordarshan says, "we are now in the age of digital technology and interactive television is slowly making its niche."

With digital services satellite delivery method would gradually lose its hold as the most popular delivery method, says Guin.

A committee has been formed under the Prasar Bharati, consisting of experts from broadcasting, industry and research organisations who will beselecting the best system out of the three internationally accepted terrestrial broadcasting systems for Doordarshan.

According to top officials in Doordarshan, digital video broadcasting-terrestrial (DVB-T), a system developed in Europe, is most likely to be adopted by the committee.

"Apart from making the initial choice of standards out of the three mentioned earlier, the bigger issue would be how to use the benefits of digital transmission for the maximum business success of the broadcasting enterprise, says De.

DVB-T is popularly used in Europe, one of its most important features being that it provides a wide range of options for the transmitter operators to choose from. The system was developed by the DVB group which is a consortium of more than 230 broadcasters and others associated with the industry operating in more than 30 countries worldwide.

The intrusion of internet, right into the homes of consumers has resulted in advertising revenue losses for television broadcasters.

Now, withdigital television, broadcasters will have opportunity to fight back and regain the lost audience and advertising revenues by providing internet-type or perhaps even better data services, notes De.

Digitising is still a relatively new phenomenon in case of television transmission, even in the more advanced countries although radio broadcasting has been digitised for quite sometime now including in India.Digitising would mean significant savings in resources for television channels.

With respect to STAR TV, Mohan says, "we have re-invested our entire savings from digitisation-into the channel." In other words, the network has been able to pump back its considerable internal accruals into the business.

According to De, "digital TV creates new business opportunities which both existing broadcasters and new entrants will need to be aware of if they are to remain industry players." "More importantly," he adds, "the more economical use of channel bandwidth enabled by digital TV will mean the capability for agreater number of broadcasters and higher revenues for regulatory authorities."

So far as Doordarshan is concerned, one of the major factors in selecting a new system lies in re-using the existing network and equipment. So that costs can be minimised, says Guinn. In fact, the core committee is still working out the costs involved in converting from analog to digital system.

The two systems will run simultaneously for some time. According to Guinn, adding that it would require at least 15 to 20 years before the analog system is phased out and the system becomes completely digital.

Another advantage especially with using the DVB-T system is that reception would be available directly at home, with the use of antennas.

With clearer picture quality cable operators would also be able to benefit, says Mohan.

Since cable TV operation started in 1985 there has been a virtual explosion in this segment with an estimated more than 75,000 cable networks across the country providing TV services to around 18million homes.

Digited technology has opened up new vistas of broadcasting, where viewers would get the benefit of reception at home, says Guinn, adding that "delivery of TV service direct-to-home (DTH) is now a very well established technology."

DTH service is possible through Ku-band satellites which have sufficient power enabling the reception of signals through inexpensive receiving terminals and small-size antenna.

So far as other countries are concerned, the European Union is funding a scheme called `Atlantic Project' which is in the realm of digital broadcasts. United Kingdom is already carrying on regular digital transmission using the DVB-T system and all broadcast will be converted to DTTB in a phased manner.