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List-Post: [email protected]
Date: Thu, 10 Oct 96 09:10:35 PST
Message-Id: <[email protected]>
To: [email protected]
Subject: Re: dBmargin
3dB sounds good. We generally impose a margin based on our product.
If the margin is not met, and we are down to the wire in terms of
development, we will get 3 - 4 more units and test them. If all 4
units are below the limit, then we consider that good.
However, then you should look at your manufacturing process to
ensure that that process is capable of building products that are
consistent across the line. CISPR also requires that you conduct
testing of product samples periodically to ensure that you remain
compliant.
2.8dB may be OK. Why don't you retest it on an entirely different
OATS? The level should remain within +/-2dB of that. (theoretically)
______________________________ Reply Separator _________________________________
Subject: dBmargin
Author: [email protected] at Internet-Mail
List-Post: [email protected]
Date: 10/9/96 14:43
I don't know about all of you, but I am sick of arguing with
hardware engineering managers about what constitutes
a passing EMC test and what does not.
I have seen companies impose a 6dB margin requirement,
some 5 dB, and some 3dB.
I have made the recommendation that the minimum here
should be 3dB. I thought that this was fair. Now comes
the product that has 2.8dB margin. Being a stick by the
rules type of person, I listened to the engineer explain
that it was the lousy PC his card was in not his card. So
I suggested that we prove his theory, purchase a new
machine and check the old machine versus the new
one and if there is an improvement, that I would let
the 2.8dB stand.
Of course the manager of the group tells me that as
a recommendation 3dB is good, but as a rule it
is IRRESPONSIBLE. Thus I end up with the "be
a b___ch" option of imposing the retest for the .2dB
or starting a precedence of well if .2 is okay, is .3 etc.
etc.
What I would like to do is take a pole. (must be election
year in the USA!!!!!!!!!!!) I would like all of you to respond
as to what you feel is appropriate. Then I'll run the
stats and let you what the results are. This way I can
go back to the manager with the number of certification
experts that responded and what they thought was right.
He or I will have a hard time arguing against stats.
(I am open to the possibility that I am wrong and
0 margin is acceptable).
Just reply with a number and I'll let you know what happens.
Thanks
Cynthia
[email protected]
