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Comms chips

Quellan Preps Signal-Smoothing Chips

A startup called Quellan Inc. is developing ways to send faster signals across backplanes and copper interconnects, joining a handful of other chip vendors specializing in signal integrity.

Officials announced today that Quellan picked up $3 million in funding from investors including National Semiconductor Corp. (NYSE: NSM) Quellan also announced that chairman Tony Stelliga, a former executive with the communications group at Intel Corp. (Nasdaq: INTC), has taken the CEO post.

Other investors in the Atlanta-based startup include Cordova Intellimedia Ventures, Greensprings Ventures, ITU Ventures, The University Financing Foundation, and Yamacraw, an economic development organization in Georgia.

At the heart of Quellan's technology is the ability to send four bits of information at a time, along with the equalization techniques needed to produce a clear signal at the other end. Originally, the company aimed its technology at metro and long-haul networks, bragging of the ability to send 10 Gbit/s worth of data on an existing OC48 pipe.

The goal changed when Stelliga joined as chairman last October. He figured Quellan could reap more immediate gains by targeting shorter connections, the system-to-system or even chip-to-chip links that were more likely to require faster speeds.

That throws Quellan into a startup stew with competitors such as Accelerant Networks Inc., BitBlitz Communications Inc., and Velio Communications Inc. Each is taking a different approach, but it still amounts to a mini-bubble of companies tackling the same problem.

"If you include SolarFlare Communications Inc., there's been over $50 million in venture capital money raised in this space in the last two-and-a-half months," Stelliga says.

Stelliga thinks Quellan has a chance, based on technology developed at the Georgia Institute of Technology, which turns out to be a hot spot for this kind of engineering. "Georgia Tech turns out the largest number of signal processing engineers in the country," Stelliga says.

The company employs 28, nearly all of them Atlanta-based engineers, with Stelliga anchoring an office near San Jose, Calif.

The relationship with National Semi could be a help, too, as the larger company will help vouch for Quellan in its dealings with customers.

Quellan and others are trying to make faster signals go across existing copper connections, the backplane being a primary target. It's easy to send signals at, say, 10 Gbit/s, but what comes out will be unreadable mush. The culprit isn't noise, per se, but intersignal interference -- the bits, which are supposed to occupy particular segments of time, start blurring into one another.

This is an issue for backplanes, because OEMs want to keep upgrading existing systems, rather than swapping out for new ones. That opens the possibility that existing copper backplanes might have to shoulder 10-Gbit/s signals. There's also trouble on the circuit board, because the board material and copper traces haven't been able to handle speeds beyond 3.125 Gbit/s.

Quellan tackles the problem on a few levels. First, there's that four-bits-at-a-time trick, which the company plans to accomplish with a 16-level modulation chip. (Four bits equals 16 possible zero-and-one combinations, each of which is represented by one of 16 voltage levels.) This would allow 10 Gbit/s worth of data to be sent in what's really a 2.5-Gbit/s transmission -- 2.5 Gbit/s being within the comfort level of most boards and backplanes.

Quellan also has its own equalization methods that will be applied in another chip, allowing the user to program the levels of equalization. A third chip would handle cancellation of crosstalk on close-knit copper connections.

It appears these will be three separate chips, but Quellan isn't giving up many more details about them. Stelliga expects to say more in the second half of the year, as the chips approach sampling.

— Craig Matsumoto, Senior Editor, Light Reading

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