From: Kyle L. Webb (hartreef@concentric.net)
Date: Mon Apr 12 1999 - 21:22:14 MDT
Christian Weisgerber wrote:
>
>
> It's hard to pick out just what they are talking about among all the
> idiot babble, but I suspect it's spread spectrum technology. The
> military has been using that for, what, 40 years? I think the tombs in
> the EE library at my university that deal with this stuff go 20+ years
> back.
Close, but not quite. I wondered when this would resurface. It is spread
spec of a sort, but done because the Fourier frequency spectrum of an
extremely short pulse is extremely broad. There was a flurry of interest
in this in Av Week and some other military journals in the late
80s/early 90s. There was talk of it not panning out on one hand because
the technology just wasn't quite there (which is my leaning), and on the
other hand that funding was curtailed because at that time partly
because of concern that the extremely wide band of frequency emitted by
a pulse radar could detect a conventionally stealthed aircraft (The
conspiracy side of it, that I had doubts about). In any case it vanished
for some years, but the article indicates that the high frequency SiGe
transistor technology that IBM among others has been developing may make
it viable now by allowing the tight timing limits needed.
Another interesting idea that came out about the same time was some
surface acoustic wave delay line signal processing systems done by EDI
that also promised some pretty amazing radar advances (don't they
always? ;). Looked quite interesting, though, again, the technology
didn't look like it was quite there, and it slipped back out of sight. I
rather wonder what happened to that bunch. I'll check up on them again
in a month or so when I move back to the Urbana area (where they were
based).
Kyle L. Webb
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