[SI-LIST] Re: Differential balanced measurements.

  • From: JS <jsven007@xxxxxxxxx>
  • To: "mark.marlett@xxxxxxxxx" <mark.marlett@xxxxxxxxx>
  • Date: Wed, 6 Nov 2013 21:56:07 -0800 (PST)

Hi
 Thanks for input mark. This is because the two single-ended signals are 
out-of-phase when forming a differential signal it seems to me. All balanced 
measurements can be computed from single-ended measurements. So, 'SDD21' is 
really just a composition of single-ended S-parameters.  




On Wednesday, November 6, 2013 12:21 PM, Mark Marlett <mark.marlett@xxxxxxxxx> 
wrote:
 
JS,
I assume you are asking for an intuitive understanding and not a
mathematically rigorous one.
If so the answer is:
SDD is the differential signal with no other content
S21 and S43  contains differential + effects from other nodes say do to
common mode signalling--- Since only one port is being stimulated wrt to
the others.
S23 and S41 contain the other effects.

So to get purely differential signalling the other effects need to be
subtracted off.

Obviously the rigorous analysis also bears this out.

Best Regards,
Mark









On Wed, Nov 6, 2013 at 9:01 AM, JS <jsven007@xxxxxxxxx> wrote:

> Hi,  Could someone help me, since I know there are a lot of SI experts.
> Could someone confirm why in the differential calculation:
> SDD21 = 1/2 (S21 - S41 - S23 + S43) The crosstalk terms of  S23 and S41
> are subtracted from the loss terms (S21 and S43)? For example, for each
> conductor of the differential pair the above equation becomes:
> Conductor 1 S21 (thru loss) – S23 (crosstalk)
> Conductor 2 S43 (thru loss) – S41 (crosstalk)
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
> List forum  is accessible at:
>                http://tech.groups.yahoo.com/group/si-list
>
> List archives are viewable at:
>                //www.freelists.org/archives/si-list
>
> 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

or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list

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


List forum  is accessible at:
              http://tech.groups.yahoo.com/group/si-list

List archives are viewable at:    
        //www.freelists.org/archives/si-list

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

or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list

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


List forum  is accessible at:
               http://tech.groups.yahoo.com/group/si-list

List archives are viewable at:     
                //www.freelists.org/archives/si-list
 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts:

  1. Home
  2. si-list
  3. Archive
  4. 11-2013