New Chip Turbocharges Copper Cabling

A small chip mounted in the plug housing could enable copper high-speed data cables to be thinner, lighter, and run further, its inventor has claimed.

Quellan said that the chip, which reduces analogue noise on the line, could be used in a range of high-speed cables, including InfiniBand, SAS, PCI-Express and 10Gig Ethernet.

It has already signed U.S. cable maker WL Gore as a customer for it, and demonstrated cables using it at a recent conference on high-performance computing.

The chip, called Q:Active, turns a passive cable into an active one, said Quellan chairman and CEO Tony Stelliga. He added that, unusually for a modern active circuit, it uses an analogue processor rather than digital.

He claimed that as well as potentially quadrupling the reach of 10Gig Ethernet or InfiniBand, say, the technology could reduce high speed data center cables from something the size of a garden hose to the diameter of CAT5, cutting their weight by two-thirds in the process.

“Weight is a huge issue — a data center can have three tons of cabling, and that weighs on the back of your servers as well as blocking the cooling space,” he said.

“We remove wideband noise with a small active device. Noise cancellation has been around for a long time in audio, but at radio frequency it’s an entirely different technique. We’re operating at one million times the frequency but the same power consumption.”

The scheme requires a chip at each end, mounted inside the plug. The chips work by adaptively tuning to the expected signal, and then calculating and subtracting the coupled noise — in effect, they learn the cable’s characteristics and alter the signal to suit them

“The coupling channel is fairly static, so once it’s learned, it doesn’t change so much,” Stelliga said.

The technology has parallels with electronic dispersion compensation (EDC) techniques such as those developed by companies such as Clariphy and Quake (now owned by AMCC) for use in fiber optic PHYs. The difference is that Q:Active is entirely analogue, whereas EDC digitizes the signal and uses DSPs to process it.

“It’s a small chip with four lanes of processing, at 60mW per lane,” said Stelliga. “It builds on our ability to calculate phase amplitude density in the analogue domain and do it dynamically, like pulling out a spread-spectrum signal — it’s maths that used to require a huge rack of equipment.”

He claimed that Q:Active should not make cables more expensive, arguing that its cost of perhaps US$5 a chip in volume would be outweighed by the savings from needing less wire, especially as copper metal is expensive.

However, if Q:Active really does bring the benefits claimed for it — cable range, weight and diameter – it is hard to see cable vendors really giving those away with no price-premium.

-Bryan Betts, Techworld.com (London)

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