Hello All,
I see by the replies that I didn't state my problem clearly. I don't mean to
imply that the devices are variants of each other they are not. They are
separate devices each of which has been tested to the full extent required.
The proposition is purely this. Since I notified the PTTs
RE: RTTE Directive Notification PeriodAs always, people are pragmatic, and
technical reasons, how valid they may be, cannot prevail
over legal ones. Any compliance matter will (-in case of dispute-) finally
be judged by
a legal specialist, not a technical-, and if in the end you manage to
convince
We are also in the process of setting up a 3 meter indoor site. Would it
not be better to compare a 3 meter site to a 3 meter site vs a 10 meter
site and add 10db to your limit line?
Joe Martin
Neven Pischl npis...@cisco.com@ieee.org on 01/11/2001 08:12:38 AM
Please respond to Neven
My understanding is that quite good correlation can be drawn between three
and ten meter sites, as long as the EUT is in the far field of the antenna
AND the antenna is in the far field of the EUT at both separation distances.
However, if this is not the case, then you have problems.
--
Hi Ken,
Very true. I was simply looking at the question of which of the two listed
methods would work best, without taking into account the overall accuracy of
either method. No matter what you try, you will never get direct
correlation between a 10m OATS and a 3m chamber, but by utilizing one
Have to take strong exception. If EUT is much larger than comb generator, a
correlation between sites using the comb generator will not work for the
larger EUT. Measurement antenna is in far field of comb generator on both
sites, but is more in the far field of the EUT at 10 m than at 3 m.
E1 cable, which is 26 AWG, is 120 0hms and T1 is 100 ohms. Impedance will
vary depending on things such as; shielding, wire gauge, twists/ft, etc.
Bill Fleury
-Original Message-
From: William D'Orazio [mailto:dora...@cae.ca]
Sent: Thursday, January 11, 2001 8:49 AM
To: EMC Posting
Hi Kevin,
Unless you give it the same model number etc., there will always be what
appears to someone who tries to check on it, an un-notified(is that a word?)
product on the market. I suppose you could have notified a family of
products if you had visibility of them prior to the initial
If you don't have a network analyzer, you can a good handle on the impedance
using a signal generator, scope and a resistor. Make sure the electrical
length of the cable is much larger (10X) than the rise time of the
generator. Load one end with 100 ohms or so and connect the generator and
scope
This is the text of the scope from the standard.
-
1.1 Scope and object
This International Standard applies to low-voltage switchgear and
controlgear ASSEMBLIES (type-tested ASSEMBLIES (TTA) and partially
type-tested ASSEMBLIES (PTTA)), the rated voltage of which does not exceed
1
Hi William,
This is a dynamic quantity dependent on the size of the wire, number of
twists, and frequency range of interest. You can get a lot of good
information from the web pages of various twisted pair cable manufacturers.
The normal impedance for twisted pair sold as CAT 3 and CAT 5 (and
Allen,
We just did this in our 3-meter lab using a comb generator. After
interviewing several test labs, I found out that they use comb generator's
occasionally to see if they are still properly calibrated. Evidently, a
good comb generator will give a consistent output, give or take 0.5dB,
I would assume that the 10m semi-anechoic chamber complies with ANSI C63.4
volumetric NSA. I would also assume that the 3m chamber noes not comply.
The major correlation issues would relate to:
1) 3m versus 10m (regardless of the sites)
2) non-compliant room (with peaks and nulls) versus
If you don't use a source of similar size to the EUT you won't get the right
answer.
--
From: Tudor, Allen allen_tu...@adc.com
To: EMC-PCST (E-mail) emc-p...@majordomo.ieee.org
Subject: Site Correlation
Date: Thu, Jan 11, 2001, 7:58 AM
Greetings:
What's the best way to correlate a
Zo= eta(free space)/ (pi * sqrt(epsilon effective) * inversecosh (D/d)
where epsilon effective is = 1 + (.25 + 0.0004 theta^2)*(epsilon of
insulation-1.)
use 0.001 instead of 0.0004 for soft insulation
theta= inversetan( twists per length * pi * D)
D= diameter of coductor + insulator
d =
The old style B insulated wire used for telephone drops and similar lamp
cord when twisted always made good balanced feedline for antennas with an
impedance somewhere around 70 ohms. This assumes conductors in the range
16-18ga. a.w.g. with rubber insulation.
Ralph Cameron
EMC Consulting and
William,
If you want to calculate the impedance, the equation for a lossless line is
simply
Z = sqrt(l/c)
where
l = per unit length inductance
c = per unit length capacitance.
For lossy line, it gets more complex:
Z = sqrt((r+jwl)/(g+jwc))
where unit length parameters are
r = resistance
I agree. We use the same regulatory ID number on a product which include
variants not affecting the rf properties. We see no reason to apply to the
Notified Body for an opinion of compliance nor to notify the PTTs when a new
variant is marketed where the rf properties have not changed. That new
My experience is that it is in the order of 75-150 ohms and depends upon the
material, lay and shielding, if any. Increased lay and shielding will reduce
the impedance.
Richard Woods
--
From: William D'Orazio [SMTP:dora...@cae.ca]
Sent: Thursday, January 11, 2001 9:49 AM
To: EMC
Allen,
the main problem you will have is not whether to use signal generator or a
comb generator, but the difference in the radiation characteristic of your
source for correlation and the DUTs that you will later put in the chamber.
You will measure a lots of near-field in you 3m or smaller
Information Workshop and Buffet Supper:
ELECTROMAGNETIC COMPATIBILITY EUROPEAN DIRECTIVE UPDATE
at the London Business Innovation Centre, Innova Park, Enfield
on Wednesday 24 January 2001, 6.30pm - 9pm
This essential workshop will give you the
All,
EN 60439-1 is titled Low-voltage switchgear and control gear asemblies -
Part 1: Type-tested and partially type-tested assemblies and is listed as a
harmonized standard under the EMC Directive.
Does any one know the scope of this standard ???
If you know the scope, does it apply to
Hello all
There are a few variables that need to be addressed to answer this question.
The first is the nature of the chamber. My reply will assume that this is
a fully anechoic chamber (walls, floor, and ceiling all lined
with absorber material). Otherwise, all bets are off due to the
Hello Sages,
I am trying to assess what could possibly happen under the following
scenario for the notification period. Lets say I had some SRD devices that
have gone through the notification period without comment. At some later
point I decide to introduce further devices in the line. The
Does anybody know the characteristic impedance of a twisted pair?
Thanks in advance,
...OLE_Obj...
William D'Orazio
CAE Electronics Ltd.
Electrical System Designer
Phone: (514) 341-2000 (X4555)
Fax: (514)340-5552
Email: dora...@cae.ca
---
This
Greetings:
What's the best way to correlate a pre-compliance chamber (smaller than a 3m
chamber) to a 10m anechoic chamber? Should I use a signal generator and
antenna or should I use a comb generator?
Would the answer be different if I were correlating the pre-compliance
chamber to an OATS?
Bill,
For plugs/sockets for overseas and information as to which is appropriate
for which countries a good source is Panel Components Corp. Check out their
website at www.panelcomponents.com and click on Guide to Worldwide
Plug/Socket Patterns Power Mains. It will detail the plugs/sockets and
As can we. ITS has been approved by Gosstandart to issue the GOST-R mark
required for Russia.
Bob Martin, P.E., N.C.E.
Intertek Testing Services, NA
978-263-2662
fax 978-263-7086
www.etlsemko.com
-Original Message-
From: rar...@us.tuv.com [mailto:rar...@us.tuv.com]
Sent: Wednesday,
Hello to all in the group,
I have been inundated with questions from the executive staff from my
company and would like to field these questions with the listserv group:
1. There has been talk about CISPR accepting 3-meter Semi anechoic full-size
chambers for CE Compliance. If this is true when
Courtland, you can reach me on my cell at 403-615-4672. We can help out
here.
Regards,
Regan Arndt
TUV Rheinland of North America, Inc.
Thanks Vitaly.
Gorodetsky, Vitaly vgorodet...@canoga.com@ieee.org on 01/10/2001
10:44:14 AM
Please respond to Gorodetsky, Vitaly
The component is marked, does not comply...?
I haven't seen that one yet.
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
peter.tar...@sanmina.com
-Original Message-
From: acar...@uk.xyratex.com [mailto:acar...@uk.xyratex.com]
Sent: Wednesday,
Hi, KB.
It is incorrect that IEC825 does not apply to components. In the case of
components, the worst case emissions, based on power supply and any other
factors that affect output power/energy must be considered.
The FDA requirements in 21CFR requires all laser sources, devices or
products to
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