🚀 go-pugleaf

Joerg a �crit :
> Fred Bartoli wrote:
>> John Larkin a �crit :
>>> On Thu, 25 Jun 2009 16:31:09 +0800, TonyS <scarborofun@gmail.nspm.com>
>>> wrote:
>>>
>>>> John Larkin wrote:
>>>>> On Wed, 24 Jun 2009 21:42:07 -0700, <castlebravo242@att.net> wrote:
>>>>>
>>>>>> "David L. Jones" <altzone@gmail.com> wrote in message 
>>>>>> news:h8B0m.53620$FI5.3564@newsfe12.iad...
>>>>>>> Check out a rather unusual phenomenon you can see on your 
>>>>>>> oscilloscope in my latest blog (#14):
>>>>>>> http://www.alternatezone.com/eevblog/
>>>>>>> See if you can get it to happen on your scope!
>>>>>>> I'll offer a free subscription to my blog for the best screen 
>>>>>>> shot posted :->
>>>>>>>
>>>>>>> Oh, and the probe doesn't have to be shorted either.
>>>>>>>
>>>>>>> Have fun.
>>>>>>> Dave.
>>>>>>> -- 
>>>>>>> ================================================
>>>>>>> Check out my Electronics Engineering Video Blog & Podcast:
>>>>>>> http://www.alternatezone.com/eevblog/
>>>>>>>
>>>>>>>
>>>>>> When I worked a Century Data we had a problem with our new reel to 
>>>>>> reel vaccuum column tape drive when ever someone would walk by the 
>>>>>> drive when it was reading it would get data errors. The problem 
>>>>>> was that the shield on the cable from the heads to the preamp was 
>>>>>> grounded on both ends.
>>>>>>
>>>>>> Bob
>>>>> That's usually the best way to ground shields.
>>>>>
>>>>> John
>>>>>
>>>>>
>>>> IIRC head signals mostly went via twisted pair. If they had a shield 
>>>> as well we would certainly not ground them on both sides.
>>>>
>>>
>>> You *want* large amounts of high-frequency common-mode noise?
>>>
>>
>> Probably. Lots of people don't understand this and I've seen this kind 
>> of mistake (opened shield) recommended in lots of highly regarded EMC 
>> books.
>>
>> But that's really nice for us. (Joerg?)
>>
> 
> Yeah! But shhht, don't spill the beans here, at least not until I am 
> retired :-))
> 

I think I'll retired after you, but this kind of misconception is 
sufficiently widely spread that we don't have to worry :-)

-- 
Thanks,
Fred.