Many analog devices such as smps emit (conduct) terrible noise in the radio
spectrum yet they are exempt. How come? I can cite the supplies for low level
halogen/xenon lighting , exercise treadmills and some computer displays. A
switch is a switch is a switch and anything that breaks current is capable of
generating harmful interference- analog is no exception. The higher the
current - the worse the spectral effluent. Where's the rationale there?
Ralph Cameron
EMC Consulting and Suppression of Consumer Elelctronics
( After sale)
----- Original Message -----
From: Tania Grant
To: Doug McKean ; EMC-PSTC Discussion Group
Sent: Wednesday, August 01, 2001 12:15 AM
Subject: Re: Test Equipment ...
Doug, et al,
FCC Part 15 addresses digital devices only. And they continue to use the
term "digital" over and over again. The scope of FCC Part 15 does not address
analog devices, whether they be industrial, commercial, or medical test
equipment. However, the FCC are exempting (and some say temporarily) digital
devices that are "used exclusively as industrial, commercial, or medical test
equipment." Therefore, no, a company that makes analog test equipment does
not have to EMC test such products. (And someone tell me please how exactly
they would test them if they wanted to!)
taniagr...@msn.com
----- Original Message -----
From: Doug McKean
Sent: Tuesday, July 31, 2001 5:46 PM
To: EMC-PSTC Discussion Group
Subject: Re: Test Equipment ...
"Price, Ed" wrote:
>
> Doug:
>
> The rationale that I recall is that test equipment is expected to be
used by
> people who understand the nature of electrical measurements and
safety.
> These people will have the knowledge and resources, beyond those of
a
> typical consumer, to recognize and ameliorate interference and other
> problems. Further, it is argued that compliance measures might
hinder
> absolute accuracy and sensitivity of measurement equipment. Also,
that test
> equipment is not usually manufactured in numbers comparable to
typical
> consumer equipment, so the impact on a society is less.
>
> IIRC, there is a somewhat shorter and simpler explanation buried
somewhere
> in Part 15.
Okay, follow me on this for just a minute.
" 47 CFR, 15.103, Exempted devices.
(c) A digital device used exclusively as industrial, commercial,
or medical test equipment."
The important word is "digital". Why just digital? Does this mean
if a company makes analog industrial, commercial, or medical test
equipment, that equipment MUST be tested?
Regards, Doug McKean (slowly becoming more confused ...)
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