On Mon, 24 December 2001, "alex" wrote:
> The sensitivity of an IC to it's environment,
> depends on SYSTEM design and
> not on the IC itself. Otherwise we would not have
> Satellites, Deep Space
> Probes or a Space Shuttle today.
This is a mistatement. Sure there are "system level"
techniques to render a probe or other complex device
capable of operating after some cosmic radiation
damage, but there are definitely technologies of ICs
that have inherent "radiation proofing" advantages
over the more standard, off-the-shelf varieties. Even
the various off-the-shelf technologies vary greatly.
The old CMOS devices were so highly susceptible to ESD
that they were essentially banned from military use.
At one time, anyway, I believe the Shuttle used core
memory - in large part because it is rad-hard.
There are special "rad hardened" semiconductor devices
designed SPECIFICALLY to operate in space where they
are subject to various particles that would never be
seen by earthbound devices. These devices are by
their nature less susceptible - and are not "simply"
some standard IC souped up by some external parts or
system.
I, too, have pondered the tradeoffs of sticking a PIC,
8051 or other device (simple or not) out at the
antennas, but the low-tech approach (a multi-conductor
cable) often makes the most sense. Yeah, it's neat
to whip up something elegant, but since one is likely
to need a bunch of relays out there anyway, why not
use them to do the decoding? Elegant or modern alone
does not make a design better. We aren't talking about
wiring up an F-16... for most ham installations,
running cable is cheap or free. Not everyone has
access to a PIC programmer.
Mike N2MG
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