[ntp:questions] If the EMI shoe was on the other foot...

Unruh unruh-spam at physics.ubc.ca
Sat Oct 10 00:21:39 UTC 2009


Michael Deutschmann <michael at talamasca.ocis.net> writes:

>In this group, recently there has been discussion of the annoyance of
>spread-spectrum clocked motherboards.

>Now, while *how much* spread spectrum hurts timekeeping is debatable, it
>obviously won't help.  Since most of us just don't care about the EMI we
>might emit, clearly we want it OFF.

>And yet, I recall in earlier months some bemoaning of the fact that
>WWVB-like radio time services are often unusable due to EMI from
>factories.  Such people might want the authorities to crack down.

>So, out of curiousity:

>Suppose all personal computers used the same FSB clock speed, which
>happens to be the same frequency as a highly useful public radio clock
>signal.

>Would the experts here then want the government to mandate spread
>spectrum be ON, and if so, what sort of modulation to use?


Ssorry you postulate a hypothetical and then ask how people would react. 
I would react by saying that the computers should be screened so they
did not emit on those wavelengths. 
Note that all personal computers do NOT use the same FSB clock speed,
and it is not on the same frequecy as a higly useful public radio clock
signal. And anyway, shielding should be required. 
Simply spreading out the garbage is not an answer.
(This is like asking-- if there is a garbage strike would you want
people to put their garbage into bags and pile them up together or not
use bags and spread it out evenly on the streets. 





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