[SI-LIST] Re: PureMode VNA vs 4port VNA
- From: dgun@xxxxxxxxxx
- To: si-list@xxxxxxxxxxxxx
- Date: Tue, 05 Apr 2005 08:56:18 -0800
Ray,
Brad and Pat gave excellent summaries. I just want to comment on
the pure mode advantage. Brad claims that ATN did not find an
advantage to using the pure mode analyzer. This is contrary to
the findings of Bockelman and Eisenstadt in "Accuracy Estimation
of Mixed-Mode Scattering Parameter Measurements", where they
directly compare both methods. (Admittedly, they use Monte Carlo
simulation rather than actual measurements, and make some
assumptions about the error model to make things easier.) They
conclude that mode-conversion parameters can have "substantially
lower error" using the pure mode VNA (by an order of magnitude or
more). Interestingly, they also mention that for four-port
devices that do not operate differentially, the pure mode results
in higher measurement uncertainty.
Now we know that theory does not always work out in practice, but
I personally feel the jury is still out until a second group can
verify ATN's findings.
--
Daniel
From: "Ray Anderson" <ray.anderson@xxxxxxxxxx>
>=20
> Over the past year or so there has been a lot of discussion of
> mixed-mode s-parameters, why they are useful, conversion of single-ended
> to mixed mode, etc., etc....
>=20
> As I understand it, mixed-mode s-parameters can be mesasured with a true
> pure-mode VNA, with a 4-port VNA, or with a TDR (the last 2 methods
> requiring mathematical post-processing of the measured data to create
> mixed-mode s-parameter data). This post processing can occur either in
> the instrument (with appropriate firmware) or after the fact in a
> separate compute environment.
>=20
> Is it true that a true pure-mode VNA is still not available commercially
> from any of the test equipment vendors? I wonder if anyone knowledgable
> on the topic can comment in the practical differences a user should be
> aware of when utilizing a 4-port VNA to measure mixed mode s-parameters
> as opposed to the fabled pure-mode instrument.
>=20
> -Ray
>=20
> --
> Raymond Anderson
> Senior Signal Integrity Staff Engineer
> Product Technology Dept.
> Package Engineering Group
> Xilinx Inc.
--=20
___________________________________________________________
Sign-up for Ads Free at Mail.com
http://promo.mail.com/adsfreejump.htm
------------------------------------------------------------------
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 FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
List archives are viewable at:
//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:
