Hello Group,
I presented a question to the group regarding EN55013 Clauses 3.2 and
3.5. and the application of the quasi-peak or average test methods and I
receive the following response:
"You must make a Quasi-Peak measurement. Provided this
measurement is below both QP and Average limits you do not have to make an
average measurement. If it is not below the average limit you will also need
to make an average measurement and compare that to the average limit.
The reason for this is that the average reading will never be higher
than the QP measurement. The standard is trying to save you time by not having
you make unnecessary measurements. The clause only applies to conducted
emission measurements.
Having said that I notice that disturbance power has QP and average
limits. Although not stated in the standard you could still apply the same
rationale to disturbance power measurements. If the QP reading is below the
average limit there is no need for Average measurements since they will also be
below the limit."
I understand that Clause 3.2 requires conducted measurements to be
verified with the average measurement method (possibly because the low
frequencies have long on and off durations which could affect quasi-peak
measurements?). I question however, whether a requirement in one clause (3.2)
can or should be applied to another clause (3.5) when the limits for quasi-peak
measurement are clearly defined in Clause 3.5
with no reference to the paragraph in 3.2 regarding the concern for average
measurement verification.
In other words, do I believe in and interpret the standard as it is
written, or not? I would like to take the position that the committee that
produced the EN55013 standard wrote Clauses 3.2 and 3.5 the way that they are
for reasons that (apparently) are not common knowledge.
Perhaps this issue has been or is being addressed in the EN55013
technical committees and I was hoping that someone from the committees could
shed some light on this matter. I am prepared to accept the application of the
average measurement paragraph in Clause 3.2 to Clause 3.5 as long as an
"official" source declares this as an appropriate deviation to what the
standard presently says and indicates that EN55013 is being changed to reflect
this understanding.
My reason for asking this question is to clear up the confusion in my
mind regarding this issue... and maybe we can all learn something in the
process. I also like to see standards that "say what they mean and mean what
they say" - at least as much as is practicable... (I know I am dreaming, but
I've got to try!)
Kaan L. Gregersen
