Is it premature for analog requiem?
The recent adoption of an accelerated schedule for DTV deployment in the U.S. has caused some in the popular press to suggest that the sole surviving technology for terrestrial domestic broadcasting will be digital, and that analog NTSC will rapidly fade away. There are several reasons why this may not happen at all.
The deployed base of NTSC television receivers in the United States is huge. More than 250 million receivers plus another 175 million VCRs — all of which are exclusively analog NTSC — exist in about 100 million American television households. Additionally, Americans purchase about 25 million receivers and about 14 million VCRs each year.
The American viewing public has yet to be exposed to broadcast DTV, and broadcasters have yet to ascertain a viable business plan for the new capital expenditures. Early predictions by the Consumer Electronics Manufacturers Association (CEMA) of the Electronic Industries Association (EIA) project first DTV receivers to have a cost of around $5,000. New VCRs will be at least $1,000. The consumer's willingness to spend such unprecedented sums on a large scale for television has not been tested. There is the promise of digital set-top adaptors, but they will cost at least $500. What motivation would drive consumers to spend this kind of money to get this programming?
It will take at least three years of availability at market for any uptick of consumer acceptance to materialize. Given the optimistic schedule of 40 top-market stations on the air with digital by mid-1999, the migration won't be a national rush, but rather, a market-by-market crawl.
Surprisingly, there is very little talk of HDTV. Most of the broadcaster interest seems to be in SDTV. So the digital offering to consumers is not better TV, but more TV. That may not be an attractive trade-off for the high costs of the new television receivers and VCRs.
While the FCC is postulating the return of analog broadcast spectrum, it has no authority to forbid cable from continuing to serve the huge installed base of analog TVs and VCRs. Such a vast marketplace cannot be ignored; cable will continue to service this important audience. From the broadcaster's point of view, it will be politically unacceptable to be denied access to analog television receivers if cable operators continue to have that marketplace.
From the consumer's point-of-view, it will be politically unacceptable to disenfranchise the consumer's television set. Consider the furor raised over the problems of cable's set-top box and the potential interference with features of television receivers . Imagine rendering the television useless and requiring the purchase of an expensive new digital receiver or a digital set-top box adapter!
A logical conclusion is that analog television will be with us for at least a couple more decades. Cable's huge capacity will assure consumers continued use of their analog TVs and VCRs, while simultaneously providing digital signals to those who can afford and who want them.The broadcaster's opportunity
There are a number of opportunities for broadcasters. During the period of transition, when an analog and a digital channel are available, the digital capacity of the analog channel should not lie fallow. It should be put to good economic use.
The Supreme Court recently upheld the "must-carry" rules to preserve local broadcast in the face of a heavy First Amendment price. Using this logic, how can it allow local broadcasters to meet their demise in the face of the high costs of a digital upgrade? How can the Court and the political system allow economically disadvantaged voters to lose the utility of their existing analog receivers?
If a digital signal is hidden in the analog signal, the value of the spectrum increases. Not only does it serve those who cannot afford new receivers or adapters, but it also serves those who can make such a purchase. The electronics for digital reception are complimentary to the need of digital signals hidden in analog. When a digital receiver or set-top box is not accessing the digital part of the spectrum, most of those same circuits can be extracting a digital signal out of the analog signal at little additional cost.
The broadcaster may find this double value of the existing spectrum to be a compelling reason for not surrendering it at the appointed time.Cable vs. broadcast data in analog
Because cable's spectrum is much more well-behaved than the broadcast spectrum, several significant advantages accrue. A time domain equalizer may not be necessary. If one is included, it may have relaxed specifications, leading to lower cost. There is no "airplane flutter," i.e. Doppler effect, from approaching or receding aircraft. Because the spectrum is better behaved, less error detection and correction is required for a given level of performance. While 8-VSB is used for broadcast, 16-VSB was developed for cable, allowing two HDTV signals in 6 MHz on cable. 16-VSB does not have twice the data capacity of 8-VSB. The doubling of payload comes because 16-VSB requires significantly less data protection. If this same approach is applied to the techniques proposed for data carriage in analog television signals, more of the raw data capacity can be harvested for payload purposes. This approach has not been well explored and offers a significant opportunity. An additional advantage is cable's availability of multiple channels to carry data. The data carrying capacity of a cable system is just huge!
Contact Walt Ciciora at: email@example.com