Article View: sci.techniques.testing.misc
Article #2Re: need to measure char. impedance of SCSI cable--how?
From: Jonathan M. Elson
Date: Thu, 18 Apr 1996 06:25
Date: Thu, 18 Apr 1996 06:25
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Rick Kerman (rkerman@brutus.bright.net) wrote: : In Article<sonicpty-1504962241210001@ppp140-sf2.sirius.com>, : <sonicpty@sirius.com> writes: : : > I want to find a way to measure the characteristic impedance of SCSI : > cabling, preferably using readily-available or inexpensively fabricated : > test equipment. : > I tried measuring SQRT(Lseries/Cshunt) using a vintage GenRad : impedance : > bridge (@ 1kHz) and got reasonable values of Cshunt, but the bridge : lacked : > low inductance resolution and could not produce meaningful numbers for : > Lseries. : > Hitting the cable with some RF frequency and using an SWR meter has : > been contemplated, but i am concerned about the effects of the : connectors, : > the need for knowing the exact length, and my lack of an SWR meter. : > : > Ideas and suggestions please? : > : > TIA, : > ))Sonic(( : Knowing the capacitance per unit length should be sufficient. Equations : for transmission line impedance can be found in most RF textbooks, and in : the ARRL Handbook. : Rick Kerman <rkerman@brutus.bright.net>
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Path: arc1-ca.pugleaf.net!newsreader.wustl.edu!coconut!jmelson From: jmelson@artsci.wustl.edu (Jonathan M. Elson) Newsgroups: sci.techniques.testing.misc,sci.electronics.misc,comp.periphs.scsi Subject: Re: need to measure char. impedance of SCSI cable--how? Followup-To: sci.techniques.testing.misc,sci.electronics.misc,comp.periphs.scsi Date: 18 Apr 1996 06:25:37 GMT Organization: Arts and Sciences -- Washington University, St. Louis, Missouri, USA Message-ID: <4l4n91$j15@newsreader.wustl.edu> References: <sonicpty-1504962241210001@ppp140-sf2.sirius.com> <NEWTNews.829736238.1038.rkerman@rkerman.bright.net> NNTP-Posting-Host: jmelson%@coconut.wustl.edu X-Newsreader: TIN [version 1.2 PL2]