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Sampling Of Tech Terms From Emerging Tech '04

There's nothing quite like the one-two punch of the Consumer Electronics Show, immediately followed by the Society of Cable Telecommunications Engineers' annual conference on Emerging Technologies (ET), to start a new year.

Holiday blobbishness melts away. Girding for another year of technological development begins.

This week's translation strolls through a (very) short list of ET tech-talk, culled from 47 pages of notes and 422 pages of presentations.

IT'S ALL DIGITAL

A big topic, not surprisingly, was the "all-digital" cable network, and the allure of renovating those 80 or so analog channels, located between 54 Megahertz and 550 MHz, into 800 or so digital video streams.

Equally tantalizing in all-digital is an extra carrying capacity of 3.1 Gigabits per second (80 channels times the 38 Mbps that comes with 256-QAM, or quadrature amplitude modulation, for those who want to do the math). That's on top of the existing, aggregate digital capacity of 1.3 Gbps, which gathers from 550 to 750 MHz.

The great thing about ET is the volume of weird stuff you probably hadn't thought of before. One dense but interesting presentation, for example, examined what could happen to common plant equipment, if all the analog restrictions go away.

For starters, plant becomes way more muscular than before. Specifically, plant components would need less oomph to move signals from, say, a laser to a receiver, said the presenter (who works for Harmonic Inc., so he should know.)

But because those optical receivers are designed to obey minimum and maximum signal levels, it's theoretically possible that they could go into an alarm state without the analog mother lode — they wouldn't receive enough energy to "hear" incoming signals. (Again: Weird stuff you probably hadn't thought of before.)

MIDSPLIT ME

Another outgrowth of the all-digital lectures is this golden oldie: The midsplit. In today's language, when people say "midsplit," they mean the extension of the upper border of the upstream path to 108 MHz, from where it is today (40 MHz). That existing upstream zone, by the way, is known as the "subsplit."

Anyone who recognizes that cable's upstream path is a gaunt 4% of overall cable bandwidth should see the good in a little more elbow room down there.

What's being "split" in "subsplit" and "midsplit" is the ratio of downstream (headend-to-home) bandwidth to upstream (the other direction) bandwidth. In the early days of cable amplifiers, which topped out at 220 MHz, the middle (midsplit) was at about 110 MHz.

In today's world of 750 MHz and 860 MHz amplifiers, a strict midsplit would occur at 375 MHz and 430 MHz, respectively — which sort of makes the term "midsplit" a sweet vestige of times past.

When you talk to engineers about subsplits and midsplits, they immediately go into spectrum dialect. They'll point out that the upper subsplit boundary is at 40 MHz, because off-air broadcasts of channel 2 ride at 54 MHz, or that 108 MHz is located at the top of the FM band. All of it references the FCC's rules on spectrum allocation, and who gets to use what, without interfering with each other.

MORE UPSTREAM

The point to remember is this: "All-digital" theoretically unbolts the skinny limits of the upstream signal path, toward a roomier, midsplit border.

Rare is the individual who views a roomier upstream path as a bad idea.

Clearly, the talk of an all-digital cable plant, and all its nuances, will pervade 2004. However, it's only fair to point this out: There's a growing a faction of cable's technical intelligentsia who view the all-digital cable network as borderline ridiculous. Other methods are cheaper and more effective, they argue, such as gradually dipping digital boundaries into analog spectrum, as needed, or increasing the upper digital border to 860 MHz.

Another new nugget from this year's ET is ACAP, which is associated with OCAP, which is the OpenCable Applications Platform — the industry's middleware for set-tops, or digital cable ready devices that can support portable (cross-MSO) applications.

ACAP is one of those nested acronyms, where the "A" is short for ATSC. ATSC is the Advanced Television Systems Committee, a broadcaster-heavy technical group that wants extensions for terrestrial nuances to be included in OCAP. Just an FYI on that one — it'll brew this year.

BEST GEEK SPEAK

It wouldn't be ET without heavy doses of impressively nerdy tech-speak. My favorite was this gem: "The technology used in 80-kilometer, 10-Gig optics is a distributed feedback laser with an integrated electro-absorption modulated laser." Got it.

All kidding aside: The people who attend ET like it for the opportunity to sit back for two days, programmed to receive, and to connect the dots. If past conferences hold true, much of the information imparted at ET represents the connecting lines. The dots emerge as the year unfolds.

By the looks of things, this year will have plenty of dots. I'll do my best to help you continue to connect them.

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