Digital TV does not live up to Analog broadcast.

Well, this isn’t such a big surprise to me, but there’s a very insightful article on EDN, about the new DTV system, which does not live up to the hype, and largely fails to serve the public interest: Digital TV, close but no cigar.

A couple of salient points from the article:

- DTV signals do not propagate well, as they are not robust against signal degradation. Analog TV signals degrade gracefully as signal strength weakens – the critical parts of the signal are strong, so the broadcast remains usable even with very poor reception. DTV on the other hand is all-or-nothing. If signal quality is insufficient to permit recovery of the data stream without errors, it cannot be decoded at all, so both audio and video cease to function. In addition, maximum transmit power will decrease, further reducing the effective range of DTV stations. The result, compounded by poorly conceived / deliberately biased propagation studies, is that actual broadcast coverage will seriously decline relative to the existing analog system. Poor DTV reception will force many people to give up and switch to (non-free) cable or satellite.

- DTV is not backward compatible with older technologies, rendering useless a lot of existing equipment, and more disturbingly, part of our society’s emergency communication infrastructure (portable TV sets used during natural disasters, etc).

- Simple, public-domain technology can no longer be used to receive a TV signal. Instead, complex digital ASICs encumbered with an array of patent and licensing issues are required. This serves only the interests of the patent holders (the “Grand Alliance”), whom the FCC foolishly put in charge of creating the new system.

- The newly cleared spectrum has not been retained for public use, but instead sold off for exclusive commercial use, arguably constituting a hidden tax.

The article goes on to summarize the major grievances. “In short everybody wins, except the public.”

From my perspective, perhaps the only (partially) good thing to come out of this will be unlicensed use of TV band “white space”. The scheme involves a good deal of unnecessary complication to manage authorized frequencies by geographic location, and will likely suffer significant interference difficulties anyway. I’d much rather see the creation of a dedicated swath of spectrum for unlicensed use.

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