[sdiy] Poor man's EMC testing?

[Barry Klein]

First, make sure you have investigated some common layout gotchas and proper
practice sort of things:
1. dampen clock/signal ringing, proper terminations, trace separation and
ground plane stiching etc.  Look with scope for nice signals and no
oscillations on supply outputs.
2. proper capacitor and ferrite bead useage.  (MLCC's have really low
ESR...)
3. chassis grounding and design - try for a full metal (Faraday) cage.
4. Power adapter has to pass too.  Choose a quiet one, be ready for a
ferrite core in the DC cable at supply or product side depending on your
results.

Next, you need a sniffing setup.  Make your own sniffing probe set - google
for suggested designs.  Buy a spectrum analyzer on ebay for under $700 or
use a LeCroy or other scope in FFT mode.

Finally, the test site.  Look for indoors with an automated scan that takes
about 18 minutes.  Much more information quicker than a manually operated
one.  Make sure they have sniffer probes that can be setup at the test bench
for you to have them focus on a problem freq. live while you mess with fixes
on the unit.

Get it to pass indoors in such a manner then maybe look for a cheaper test
site in Asia...? for the final reports.

Barry


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Joe Grisso
Sent: Tuesday, March 16, 2010 2:01 PM
To: synth diy
Subject: [sdiy] Poor man's EMC testing?

Hey gang,

     While this is somewhat off-topic, I was wondering if anyone had
insight into economical test methods for performing EMC analysis
(FCC/CISPR) before going to certification? Most of the solutions I've
found involve purchasing a $5K+ Spectrum Analyzer and equally
expensive antenna for measurement. Are there any other methods you
guys know about?

Best,

-- 
Joe Grisso
Detachment 3, Ltd.
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