[time-nuts] Frequency counter recommendation
Javier Herrero
jherrero at hvsistemas.es
Sun Dec 19 14:04:37 UTC 2010
El 19/12/2010 12:34, Magnus Danielson escribió:
>
> Need to look at it. But essentially, during normal operation common
> mode isolation isn't all that hard. The problem is that during failure
> mode can what should be a common mode voltage and current become
> diffrential mode, which jumps straight through the transformers as a
> transient and that will burn the receiver anyway...
>
Usually I'm worried with common mode isolation, for noise and EMC
issues, more than for protection. The kind of equipment where I've used
it are used in a quite controlled environment (if there is a
high-voltage transient there, and if it toast the satellite instrument,
any damage in my equipment would be a lot lot lot less important...
almost futile :) )
> I've seen people burn their Ethernet port by hooking in an ISDN line
> to the wrong connector.
>
I can imagine :)
> A wrapped solution like the ADUM1200 puts more stuff between the
> transformer and actual receiver... so maybe you save the receiver, but
> you might toast the isolator.
>
Since usually the receiver circuit is also ahead the isolator (for
example RS422 to TTL, then isolator), it would also be toasted...
perhaps protecting the isolator :)
> For an optical isolation you might toast the transmitter, but that's
> about it. Probably that would be the least of your problems when it
> occurs.
>
Same thing...
> Cheers,
> Magnus
Regards,
Javier
>
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--
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Javier Herrero EMAIL: jherrero at hvsistemas.com
Chief Technology Officer
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