Superfast Optically-Based DSP Announced

dawgnut writes "An Israeli venture-funded startup has announced a digital signal processor chip that uses optical connections rather than silicon transistors. The result is a very fast chip with massive throughput for calculating fast fourier transforms that wastes very small amounts of power as heat. Interesting applications (or frightening ones depending on where you come down on the security vs. privacy thing) for remote sensors, biometrics and homeland security stuff." The prototype being showcased is rather large, but Lenslet is hoping to have it shrunk down to a chip within five years. Update: 10/31 00:22 GMT by CN : Whoops, we ran this yesterday. Mea culpa.

Comments

Memory is irrelevant for this kind of "processor"

[Anonymous Coward]

This is NOT a Harvard architecture part - this isn't fetching instructions from RAM and executing them, like a regular DSP would.

Think of this more like an FPGA - you have a device that is configured for a specific processing algorithm, and data is fed in at wire rate and processed at wire rate.

An example of how a device like this might be used may be in order:
I'm trying to find a radar pulse buried in the noise coming in from my receiver. I want to know the phase delay of the radar pulse - how long from when I sent it till I got it back.

Now, I know what my radar pulse looks like as it goes out. I know that any reflection is going to consist of versions of that pulse shape, delayed and of varying strengths. So what I do is called a correlation - the easiest way to think of this is to imagine having 2 transparencies, one of my outgoing pulse, and one of the incoming signal. Now, I hold them up to the light, and slide the incoming signal across the reference pulse until things match up - that's the point of maximum correlation, and that give me the delay of the signal.

A real correlation function is a bit more complicated as you have to allow for the signal level to be changed - if I am looking for a signal of N samples in a received data stream of M samples, I have to do M*N multiply and add operations to get my correlation. Now, for a radar signal I might be sampling at over a billion samples a second, and looking for a chirp of a 100 ns would give me over 100 billion MAC operations a second. There are ways to do that with conventional DSPs, but they are a galloping BITCH to do (you basically make a cluster of DSPs, and each DSP takes a part of the signal. Synchronising that is a bitch.)

This device would work by having the shape of the outbound pulse represented in the structure of the device itself, and the MACs are done by taking the incoming data stream and projecting it on the structure - thus you do all your processing in parallel, and at wire speed. You get a pulse out when the incoming signal matched the signal you ar looking for.

ps Dupe.

Re:I have to admit

[Arker]

Perhaps they develope military technologies BECAUSE they aren't popular and perhaps they aren't popular BECAUSE they're the only democracy in the middle-east AND they've been at odds with the Arabs for the past several thousand years.

If by "they" you mean Jews, you're wrong. It was Europe where they were at odds for thousands of years, the Muslim world was a relative safe haven for Jews until very recently.

If by "they" you mean the Israeli government, it's existed for decades, not thousands of years.

And, of course, the fact that "they" are unpopular with the Arab world at the moment couldn't have anything to do with the occupation, land grabbing, apartheid system, and open aspirations of ethnic cleansing of the Israeli government, which pretends to speak for Jews as a whole even though many disagree wholeheartedly with its policies. That would be far too obvious.