FW: [RFI] New chipset vs. EMI in notebook computers.

[Kevin Rowett]

The cypress part is from a company they bought a few years ago.  The
part is a crystal OSC that outputs a "Spread Spectrum" clock, rather than
a CW clock.

The idea is the clock frequency moves around just a bit - not too fast, and
not too much.  Not enough to create timing problems inside ICs, but enough
that no narrowband CW signals show up on the PCB or chassis. 

This is all targetted at passing CISPR 22 and FCC class B Part 15 emissions
limits
for unintentional radiators.  The net effect of the wandering clock is
lowering
the total power in the passband of the test receiver.

As for the units being less noisey into the radio sitting on the same table
- YMMV.

de -KR- N6RCE


-----Original Message-----
From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
Behalf Of Cortland Richmond
Sent: Monday, July 19, 2004 8:05 PM
To: rfi at contesting.com
Subject: [RFI] New chipset vs. EMI in notebook computers.


>From Electronic News Today ( www.electronicnews.com )

Cypress Ships Chips for Intel's Alviso

excerpt:
Cypress samples a two-device solution that addresses timing and EMI
reduction in notebooks, qualified by Intel for its troubled Alviso
platform. 

EMI, huh? It is RARE for a firm to admit to that particular problem.