By Peter J. Brown
The first generation High Definition Television (HDTV) was all about preparing HD-ready digital infrastructure, while second-generation HDTV is all about filling up the content pipe with programming that counts and pushing the HDTV network to do more for consumers, content producers and service providers. The satellite industry quickly is moving ahead and offering the second-generation HDTV solutions with everything from HDTV-optimized satellites to a new array of products aimed at handling much larger HDTV bitstreams.
SES Americom, for example, has already deployed the first of a pair of HD-optimized satellites that make up its HD-Prime neighborhood and, at press time, the next was scheduled for launch last month. SES Americom currently supports NBC and PBS broadcast HDTV as well as Discovery HD Theater, Showtime HD, Bravo HD and iN DEMAND (video-on-demand pay-per- view) on cable. Launched in early February with a C-band payload, Americom 10 (AMC 10) is operating at 135 degreesW. It replaced Satcom C 4. AMC 11 will soon appear at 131 degreesW, replacing Satcom C 3.
"We have built linearizers into the SSPAs [solid state power amplifiers] that improve the quality of the digital signal at the higher power levels. Our tests (both on-orbit and on the ground) indicate that we have minimized the bit errors at even the highest data rates, for example, those that would be appropriate for HD," says Carl Capista, vice president of media and entertainment services at SES Americom.
In addition, the SSPAs' output on AMC 10 and AMC 11 are 20 percent greater in comparison to the Traveling Wave Tube Amplifiers (TWTAs) output on C 3 and C 4, according to Capista. The satellites' reflectors are shaped to provide a consistent coverage pattern so that an HD signal is delivered equally in Maine, Texas and Florida, for example.
"We have people transitioning from analog to SD [Standard Definition], and this has freed up capacity for HD," adds Capista. "All the basic cable programmers have plans afoot for HD in 2005 as more cable systems are offering HD as part of their basic service lineups."
Second-generation HDTV is happening on the ground as well, and it is happening much faster than anticipated because the original model of using the full ATSC (Advanced Television Systems Committee) load of 19.4 Mbs is on the verge of becoming outdated.
"Do I agree? Absolutely," says Gil Maxwell, senior vice president and COO at Maine Public Broadcasting Corp. "Today, it is the full 19.4 Mbs, but as soon as someone figures out how to make money using some of the bits in the stream, the quality argument will quickly disappear."
According to Maxwell, the Snell and Wilcox concept of 'Mole Technology' might be seen as a first-generation solution. This involved sending the encode instructions with the video as metadata so that when decoding took place, one could use the same algorithms to recompress the signal, thus maintaining the best possible quality. In contrast, an example of a second-generation HDTV device is the new multistandard HD compression pre-processor from Snell and Wilcox known as the CPP1000 Prefix-HD, which can reduce bandwidth requirements for satellite broadcasters by eliminating unwanted signal artifacts, among other things.
"With the software today, you can inspect the stream to see what encode tools were used and then make the best decision absent any metadata as to where to get the other bits to throw away," says Maxwell. "Once you have all the extra you can squeeze out, you then start tossing information until you reach the limit you set. Our limit is 12 Mbs. When there is a lot of motion, you can start to see the results of the additional reduction."
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