At 13:05 21/03/2001 -0500, Rosen, Brian wrote:
>Well, but
> Most PC designs use phase lock techniques which keep external
> signals way below the CPU operating frequency
The usual multiplier is in the single-digit range. That's why I said "some
hundreds of megahertz". And don't forget the harmonics....a 100-MHz square
wave (or reasonable facsimile thereof) has a major harmonic component at
300 MHz.
> There are legal limits for radiation; most laptops and all
> PDA devices are "Class B" which is a pretty low level.
>The real issue I suspect is that there is no practical way to test
>what the effect of a whole planefull of "at-the-limit" devices do
>to the plane's systems. It is very reasonable to design the avionics
>to be hardened against this sort of thing, but the older planes wouldn't
>have such avionics.
control systems on older planes (pre-1970) are actually more robust,
because they use a lot more analog and hydraulics rather than avionics.
nav systems are another matter, of course.
>I expect we will see some lessening of the rules as the experience
>and turnover of the airframes proceeds. We already have the
>"mobile use okay until pushback" which is a real change.
hasn't arrived in Europe yet, unfortunately.
--
Harald Tveit Alvestrand, [EMAIL PROTECTED]
+47 41 44 29 94
Personal email: [EMAIL PROTECTED]
