[time-nuts] Interfacing a 8dBm sine output of an OCXO to adigital logic standard

David Forbes dforbes at dakotacom.net
Fri Sep 16 16:43:18 EDT 2005

Poul-Henning Kamp wrote:

> Just remember to stay well away from "spread spectrum" or disable
> it if possible.  It's a 50-75 kHz FM to make the computer sneak
> under the EMI masks.
Actually, it's a sneak to allow 15 to 20 dB greater EMI from the 
typical PC. The motherboard makers provide a control bit in BIOS to 
disable spread spectrum for normal operation, informing the user that 
it is to be enabled for agency testing only. The agencies should force 
the BIOS writers to remove that bit, since it allows the hardware to 
be rendered non-compliant under user control.

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