Like is so often said here: "It depends"
The answer lies in the nature of the EUT. Is the peak that was measured
a momentary and infrequent emission, a click, or a periodic emission
that cycles on and off due to the nature of it's operation?
As a totally made up example:
If the EUT quietly gathers data for 1 minute, then processes and stores
the data to memory for several seconds and creates higher emissions
during that period, then the failing evaluation by the lab would seem to
be justified.
As is often the case, a close examination of the equipment under test is
required.
Respectfully,
Brent DeWitt
On 12/5/2021 1:45 PM, Amund Westin wrote:
Some weeks ago I went to a test lab as an observer on a CE marking
project (IT product).
I participated on the radiated emission testing and some frequencies
were above the limit line during the scan (peak measurement). Later
on, the Quasi-Peak measurement lowered the values significant and
therefore with the result Passed.
Later on, I was told that they continued the testing by 10-15 minutes
and was logging the maximum Quasi Peak value (repetitive QP meas) on
spike with the highest value. During these 15 minutes, one or two QP
measurement was above the limit and the result was changed from Passed
to Failed.
I have not seen this test procedure before. I’m familiar with just one
QP measurement on each frequency and not Max Hold QP on each for 10-15
minutes.
Anyone who have experienced the same? Is it a CISPR procedure or just
some overzealous lab engineers?
Best regards
Amund
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