Re: [d@DCC] More research on Bill C-2: DVD players interfer with military

From: Darryl Moore <darryl _-at-_ mfe.ca>
To: General Discussion <discuss (at) digital-copyright.ca>
Date: Mon, 03 May 2004 14:17:46 -0400
References: <Pine.LNX.4.21.0405022150210.11473-100000@diamond.ansuz.sooke.bc.ca>

I'm an electrical P.Eng in Ontario. My field theory marks in university 
weren't the best, but they were OK.

If we could get more information on these cards I'm sure we could debunk 
their claims.

I don't think the theoretical possibilities are as important as the 
specific test result Industry Canada is claiming. Theoretically anything 
with an electronic clock in it is capable of causing interference on any 
number of frequencies, but they are not calling to regulate all 
microprocessor based equipment.

The main question is do the cards pass inspection as a either a Class 
'B' electronic device or an exempt device. Industry Canada's implication 
is that they do not. However the EMI requirements for a Class 'B' device 
are quite specific. It should be pretty straight forward to tell if they 
are talking through their hat. But we would need more information about 
these cards.


On 2004-05-02 9:59 PM, mskala@ansuz.sooke.bc.ca wrote:

> On Sun, 2 May 2004, Joe McGuire wrote:
> 
>>Granted it is been some years since I have done any serious work with 
>>'lectronics, and even longer since I have received my 'lectronics 
>>technologist degree, but I am fairly certain that none of these AVR 
>>cards operate with sufficient power or frequency to cause harm.
> 
> 
> It'd be nice if we could find someone really authoritative on this.  I've
> got a correspondence diploma in electronic design and an Advanced Amateur
> Radio certificate, but my *serious* credentials are all on the software
> side... and, unfortunately, the most accurate technical answer is going to
> be something like "It is theoretically possible that in some kind of weird
> circumstance a critical communications system might be subject to
> interferance from an illegal descrambler, but that would never happen in
> any ordinary situation".  I fear that some people would hear it as "Yes,
> illegal descramblers really can cause harmful interferance!"
> 
> Maybe it would be productive to *compare* the interferance potential of,
> say, descramblers and cordless telephones, instead of trying to evaluate
> the risk associated with descramblers in isolation.  If we give one "risk"
> number and it's greater than zero, then the other side will say it has to
> be exactly zero, because human beings have a hard time dealing with small
> numbers.  Giving two risk numbers and pointing out that one is much
> smaller than the other, might be a better plan.  I'm certain that cordless
> phones are riskier than descramblers, because they are actually designed
> to radiate significant amounts of power, whereas nobody actually *wants* a
> descrambler to radiate, and at worst the designers might not be careful to
> prevent it as well as we might like.
--
For (un)subscription information, posting guidelines and
links to other related sites please see http://www.digital-copyright.ca