If you have S-parameters measured for 2 line segments with the SOLT calibration
to the probe tips, you can extract Generalized Modal S-parameters
(GMS-parameters) for accurate computation of the losses per unit length and
phase constant. GMS-parameters are normalized to the characteristic impedance
of t-line and, thus, reflection-less for a t-line segment by definition.
Technically, computation of GMS-parameters is a part of TRL-calibration, but
without the 50-Ohm impedance assumption - see details on GMS-parameters
computation at the app note #2010_01 at http://www.simberian.com/AppNotes.php
(#2014_03 is follow up for both dielectric and roughness characterization). It
simply removes the effect of the launches. Though the process may be sensitive
to non-identities of the launches and traces - the extraction should be
planned. Also, S-parameters of 2 segments must be pre-qualified first and have
acceptable quality metrics and TDR that confirms that the launches and traces
are nearly identical.
Best regards,
Yuriy
Yuriy Shlepnev, Ph.D.
President, Simberian Inc.
3030 S Torrey Pines Dr. Las Vegas, NV 89146, USA
Office +1-702-876-2882; Fax +1-702-482-7903
Cell +1-206-409-2368; Virtual +1-408-627-7706
Skype: shlepnev
www.simberian.com
Simbeor – Accurate, Fast, Easy and Affordable Electromagnetic Signal Integrity
Software
2010 and 2011 DesignVision Award Winner
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of ??
Sent: Tuesday, April 14, 2015 11:38 PM
To: Kevin Voegele
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Why are there difference when calculating loss per unit
length?
Hi Kevin ,
We use micro-probe and SOLT calibration to probe tip.
Do I need any other calibration ?
Kevin Voegele <kevin.voegele@xxxxxxxxxxxxxxxx>于2015年4月15日星期三写道：
Connectors are a larger percentage of the trace at short distances.you de-embedded cables too?
Have
On Behalf Of ??
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]
Sent: Tuesday, April 14, 2015 8:41 PMunit length?
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Why are there difference when calculating loss per
measured total loss of trace,the loss per unit length calculated by different
Hi experts,
Sorry for messy code of this question previously .
We characterize insertion loss by xx.xx dB/inch usually.But after we
My question is:why are there difference ?from measurements?design ?orothers ?
any
T hanks
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