Harmonic Lightwaves Inc. will use next week's National
Show in Atlanta to debut the newest in its line of digital-headend products: a
digital-video multiplexer.
Dubbed the "MMX8000," the new multiplexer was
designed as a slide-in card that fits into Harmonic's "TRANsend" line, said
Patrick Harshman, product manager for the manufacturer's digital-systems division.
The multiplexer works by plucking MPEG-2 digital-video
streams from a variety of inputs -- like satellites, servers and DS-3 interfaces -- then
pulling them together and multiplexing them for delivery to cable or wireless cable
customers.
Not designed as a statistical multiplexer, or
"grooming" device, such as what companies like Imedia Corp. are selling, the
MMX8000 is simply a way for cable operators to manage a variety of digital-video inputs
that they want to send along to customers, Harshman said.
"It can insert new things" into a digital bit
stream -- like locally generated content and local advertisements -- "but it
doesn't reoptimize the bits," he explained.
Multiplexers are becoming an important element in cable
headends because as digital-video services become more pervasive, operators need a way to
send along not only satellite-delivered video, but digital ads.
Harmonic's overall digital headend -- which consists
of a MPEG-2 encoder card and a transmission platform -- allows integration of up to 10
encoding and multiplexing cards, "and it eliminates the need for cumbersome external
cables," Harshman said.
Each multiplexer spits out data at a speed of 54 megabits
per second.
"In principle, at 54 mbps and with each [digital-video
stream] running at 2 mbps, you could choose 25 different transport streams," Harshman
said.
The compact size of the TRANsend platform stems from a
desire by MSOs to scale up slowly and to not have to buy more equipment than they need
when getting started with digital video.
