List Members:
Searching of the EMC-PSTC, NEBS, and TREG archives has been enhanced! (NEBS
stands for Network Equipment Building System and TREG stands for Telecom
Regulatory E-mail Grapevine).
The archives were formerly available on the old IEEE Online Communities site
but when the IEEE change
Many times there seems a disconnect between what is required by a standard
and what is needed for compatibility.
_
Ralph McDiarmid | Schneider Electric | Renewable Energies Business |
CANADA | Regul
But how are those measurements made? At what distance above the ground
plane? Surly the calibration setup should
match how the antenna is used during emissions measurement, otherwise 1dB
here or there becomes meaningless.
Yes, the log amp is after the detector. The real question, though, is
where the video filter used for averaging is placed in the circuitry. If I
am not mistaken, it is placed after the log amp when using the log
vertical display. To get correct averaging for measurement, you need to
select line
In message <4edf7f60.9020...@earthlink.net>, dated Wed, 7 Dec 2011,
Cortland Richmond writes:
Sooner or later, someone will say their project passes by 0.5 dB;
SHIP IT.
It may be reprehensible, but it's realistic. The vast majority of cases
of actual interference occur when the source is
Yes, and in the real world that is what is done. But it has to meet the
accuracy requirement of the test. For example, see MIL-STD461E 4.3.1
(slightly snipped):
4.3.1 Measurement tolerances.
Unless otherwise stated for a particular measurement, the tolerance
shall be as follows:
c. Amplitud
In message <4edf523d.4090...@earthlink.net>, dated Wed, 7 Dec 2011,
Cortland Richmond writes:
An untuned loop should exhibit no resonances in its usable range. See
http://www.ets-lindgren.com/page/charts.cfm?i=6511 .
Also, A Novel Standard Loop Antenna for Antenna Calibration in the MF
and
Now we get to the heart of the matter that prompted the original post.
That spike in the 137 cm tip-to-tip biconical used with a T1 dipole balun
(28 200 MHz) behavior might have been objectionable, but you wouldn¹t miss
it an analog sweep with even 1% frequency steps. You would only miss it if
An untuned loop should exhibit no resonances in its usable range. See
http://www.ets-lindgren.com/page/charts.cfm?i=6511 .
Also, A Novel Standard Loop Antenna for Antenna Calibration in the MF
and HF Bands, ieeexplore.ieee.org/iel5/10111/32404/01513478.pdf
Amateurs have used home-made loops to
The quotation below is a little out-of-context. In the previous statement in
that post, it says, " ...the point ... is that no test-type antenna is a
high ³Q² device."
It is true that a tuned loop can be a very high "Q" antenna, but these are
designed solely for communications. No one uses such an
Bill
This is a R&TTE Directive article 3.2 radio spectrum standards not an "EMC
standard"
The standard details many parameters such as RBW, VBW, Span and Sweep time for
a number of the tests.
The "Average" detector is the a power average detector.
Where test signal do not have a 100% duty cycle
Several EMC antennas have AF step performance of 1 dB per 5 MHz or so at
certain frequencies.
If the antenna would have a linear behavior, 2 points would be enough
as all other frequencies could be linearly interpolated.
But my particular Chase BILOG 6111A has a bump at 14.1 dB at 258 M
For EMI each frequency need to be averaged discretely.
That means that time per frequency needs to allow for the
filter to settle.
Several standards (not on hand) have translated that to sweep times.
They can be very slow rates in the hour ranges.
Same for QP.
Regards,
Ing. Gert Grem
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