[SI-LIST] Re: Differential closk wiring (with no typos :)

Hi Bouchra,

I wouldn't say they are wired that way for convenience.
Two benefits occur from the routing of these signals 
together.  The first benefit is lower emi as the emissions
from the conductors will cancel each other out.  Secondly
as one is measuring the difference between the two signals,
any noise coupled on to one conductor will be invariably
be coupled on to the second thereby cancelling itself out
during the difference measurement.  This is known as common
mode noise.  

That being said, the circuit will still basically work whether
the signals are routed together or on completely different 
layers.  Lee Ritchey has an interesting paper on this very 
issue.

        http://www.speedingedge.com/docs/diffsig.doc

So, while the circuit will still work there are benefits that 
routing the signals together will afford you.

best regards,

Michael Greim

-----Original Message-----
From: BIBICHA [mailto:f_bouchra@xxxxxxxxx]
Sent: Wednesday, August 22, 2001 10:47 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Differential closk wiring (with no typos :)


(I could not read my hand writing :)

Hi all:

I am really interested in knowing if there are rules in wiring High speed
differential clocks.
We wire them parallel about 5-10mil apart and they should have the same
length (wired in the inner layer)
I learned in one of the classes that it is wired that way for '
convenience' and it is not necessary that they are wired parallel and close
to
each other.
I have to convince other people and myself with that and I need more data.

Thanks for your help
Bouchra

------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu
  
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: