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Analogue to digital: Radio slow to tune into transition 
October 13, 03


>From Marconis first transmission in the early 20th century to the satellite broadcast of the 21st century, its been quite a journey for radio. Technologically speaking, the development in the transmission system has been slow. But, points out chief engineer of All India Radio H O Srivastava that technological growth has been more prominent in studio techniques. 
Agrees US-based iBiquity Digital vice-president (marketing) David Salemi. According to Mr Salemi, while there has been significant transition in other media, radio has clung to an analogue delivery system that has not changed significantly in 100 years. 
iBiquity is the sole developer and licensor of HD Radio technology, which allows radio broadcasters to transmit a digital signal in conjunction with their current analogue signal. 
Coming to studio techniques, from linear recording earlier, its all computer-based and non-linear now. And, production is all digital. Radio professional Prashant Pandey says: Today, radio stations are very modern and sophisticated by design. The entire station design is based on the latest digital equipmentand except for the actual broadcast which is analogue (FM)the facilities are ready for Digital Audio Broadcast (DAB) with minor changes/ additions. 
AIRs Dr Srivastava gives a run down on the radio scene. Globally speaking, radio transmission began in the AM (amplitude modulated) band, and Europe and the US witnessed some of the significant developments in the area. There was growth up to around early 1930s, and then radio took a backseat due to the wars. After the World War II, things started to move, but it was in the 1960s that radio transmission took a leap technologically, with stations coming on the FM (frequency modulated) band. Although FM was gaining in popularity in the US and Europe, India was nowhere in the picture still. Till about the late 70s. Dr Srivastava explains the late entry of India in the FM scene. India did not join the FM bandwagon for long because there was much doubt on whether cheap FM receivers would be available or not in the country. 
Coming to transmission technology, it was all the way analogue till the mid-90s or so. In the late 90s, possibility of digital transmission started being explored. But, there were hurdles: bandwidth was proving to be an issue. To get past this problem, an effective compression technology was needed. Engineers in the radio world narrowed down on two compression technologies: psycho-acoustic and temporal compression. 
As a result, a number of digital systems are being tried out across the world, but none has really matured. If Europe is working on Eureka 147 terrestrial digital audio broadcasting system (which India wants to adopt), the US is focused on the IBOC (in-band on-channel) system. Digital Radio Mondale (DRM) is yet another technology that Europe is experimenting with. According to Dr Srivastava, once DRM comes, shortwave radio would be more powerful. As of now, short-wave is being phased out around the world because of its poor reception quality. The band in vogue is FM. 
That was terrestrial. There has been some action on the satellite front too. WorldSpace and XM are the two prominent radio service providers on satellite digital platform. While digital satellite (like WorldSpace) radio requires an antenna facing the satellite, thereby restricting mobility, terrestrial digital transmission is capable of greater mobility. 
In India, the only satellite digital system that we have is WorldSpace, a US-based system. According to WorldSpace head of consumer audio business Bharath Chari, there are 14 subscription channels. Of these, 11 are international and three Indian, split into two bouquets. The current estimate of WorldSpace receivers in India is around 51,000. 
India is in the process of other developments too, in terms of radio technology. 
For example, AIR is in talks with the Indian Railways to introduce satellite radio in select trains. Sahara, a private TV channel, has already sealed deals for digital radio in Mumbai local trains. 
At this point, digital receiver cost is a problem that every country is struggling with. Whether its DRM, DAB or IBOC, you need separate receivers for each one, and nothing comes cheap. Giving an estimate, Dr Srivastava says that while a DRM receiver would come for around $500, DAB could cost you in the region of $150-200, and IBOC around $500. WorldSpace receivers, that are available in India, begin at Rs 5,000. 
Indicating that cost is a major issue for a smooth run of digital radio, Dr Srivastava says that BBC introduced DAB seven years ago, but the receiver cost is not down yet. Although there are claims of DAB receivers covering 85 per cent of Europe, nobodys forthcoming on the receiver numbers. 
While theres lots happening in various branches of radio, such as community radio and even Internet radio, India is likely to stick to FM as the mainstream band for several years, say industry pundits. Other transmission technologies may come as pilots, but India would wait for a while before accepting them. Ultimately, affordability is the key! 
Source: Financial Express 


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