Academic journal article T H E Journal (Technological Horizons In Education)

Digital Compression Primed to Fuel an Explosion in Distance Education

Academic journal article T H E Journal (Technological Horizons In Education)

Digital Compression Primed to Fuel an Explosion in Distance Education

Article excerpt

Using microwaves, optic fibers and telephone lines to distribute educational programs is nothing new. Today's students can get college degrees, take continuing education classes for career advancement, or select high school specialty classes not offered locally--all without setting foot in a traditional classroom.

Until now, however, the high cost of delivering such on-the-spot education has hampered growth. No more. New technology is proving it can slash the cost of distance learning--by up to 85%.

While higher-power, Ku-band communications satellites are providing the medium for change, it is digital compression technology that is sparking the revolution in satellite-delivered education.

In the past, entire satellite transponders relayed broadcast-quality analog video signals. Compression, however, digitizes the signals and electronically simplifies their content. Thus, eight or even more channels can be squeezed through a single transponder. Once the signals return to Earth, they are electronically expanded again. The result: a huge jump in available capacity and a sharp drop in perprogram costs.

* NTU Gets More for Less

In the spring of 1992, National Technological University (NTU) became one of the first distance learning providers to cash in on the new compression technology. NTU had been spending $2 million a year to lease two satellite transponders, which delivered four channels of analog programming to 420 receiving sites. In 1991, NTU served more than 100,000 students with 800 programs provided by 130 corporate sponsors.

Now NTU's consortium of 45 universities provides 12 channels of digital programming on just one transponder. Net savings: $1 million per year. That's 300% more programs at 50% of the cost.

Tripling capacity couldn't have come at a better time for NTU. Many of its offerings are non-credit short courses in advanced science and engineering, aimed at practicing technicians, scientists and engineers. "To keep growing," says Doug Yaeger, vice president of marketing for NTU, "we needed additional channels."

The digital format also provides a host of new services that attract even more students: the ability to send faxes, turn video recorders on and off remotely to automatically tape programs, and deliver advanced programming directly to a student's on-the-job workstation--all via satellite.

* Small Users Benefit

Although many distance learning providers operate on a far smaller scale than NTU, the economics of digital compression make it just as compelling for them.

John Gwynn, director of Galaxy Satellite Services at Hughes Communications (HCI), says "occasional-use" customers typically pay from $400 to $600 per hour to buy transponder time. They also risk losing their time slot if the transponder they share is sold to a full-time user who can pay the $170,000 monthly cost.

Compression alters the arithmetic dramatically. "If we put just six channels on a single transponder," explains Gwynn, "a school could buy 24-hour access for a fraction of the hourly rates on analog transmission. They could broadcast whatever they can produce."

* The Compression Hardware

NTU uses a compression system called SpectrumSaver developed by Compression Labs, Inc. (CLI) of San Jose, Calif. Equipping a program-origination point with CLI's compression system costs about $75,000. Downlinks are between $1,500 and $8,000 each, depending largely on whether the receiving site already has a Ku-band antenna. Gwynn figures the network savings in transponder costs can pay for the equipment in three to five years.

Payoff will come faster as receiver equipment costs drop, notes Susan Brazer, marketing manager for Broadcast Cable and Multimedia at CLI. "The distance learning market is extremely important to us," she declares. "And we have a product that is incredibly well-suited for it."

* Switching to the Sky

The Indiana Higher Education Telecommunication Systems (IHETS) agrees. …

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