RE: [10GBASE-CX4] Updates on 802.3ak website
Takeshi,
I responded earlier to Chris's remark. Now I have looked at your point made
and am not convinced that the issue is of "Characteristic Impedance" as much
as it is about measurement technique.
I believe this is a measurement problem. The Zo of the cable is based upon
the distributed L and C (and some R) of the materials and unless the cable
structure changes, is constant. Therefore, one can make the assumption that
Zo as measured at the beginning of the cable is Zo.
Once that is determined, Return Loss, Insertion Loss and the other required
parameters sufficiently characterize the assembly for our needs.
Regards,
Dan
> -----Original Message-----
> From: Takeshi Okuyama [mailto:tokuyama@fcai.fujitsu.com]
> Sent: Wednesday, June 18, 2003 7:08 PM
> To: DOVE,DANIEL J (HP-Roseville,ex1); 10GBASE-CX4 (E-mail)
> Subject: RE: [10GBASE-CX4] Updates on 802.3ak website
>
>
> Hi,
>
> We have concern about characteristic impedance shown in
> 54.8.1, in case
> of longer cable assembly, measurement result indicates higher
> value compare
> to the specification. InfiniBand specification defines this
> value as 95~155 ohms.
>
> Please refer to our measurement result attached in this mail.
>
> Regards,
>
> Takeshi Okuyama
>
> FUJITSU COMPONENTS AMERICA, INC.
> 250E. Caribbean Drive, Sunnyvale, CA 94089
> Telephone: (408) 745-4933
> Facsimile: (408) 745-4971
> E-Mail: tokuyama@fcai.fujitsu.com
>
>
>
> -----Original Message-----
> From: DOVE,DANIEL J (HP-Roseville,ex1) [mailto:dan.dove@hp.com]
> Sent: Tuesday, June 03, 2003 11:30 AM
> To: 10GBASE-CX4 (E-mail); 802. 3 Working Group (E-mail)
> Subject: [10GBASE-CX4] Updates on 802.3ak website
>
>
>
> Hello All,
>
> I was informed that the D4.0 comments should be posted onto a public
> directory rather than in the private directory, so I have
> made that change.
>
> You can go to http://www.ieee802.org/3/ak/index.html and find
> a "comments"
> link now. My apologies if this caused any inconvenience.
>
> Also, Howard Baumer has provided us with the D4.01 Task Force Review
> document which is
> located in our private area. Task Force members; please
> review that document
> to ensure that it
> incorporates all of our work from Portsmouth correctly and prepare to
> discuss any issues you
> find with it via the reflector, or in Ottawa.
>
> Best Regards,
>
> Dan Dove
> Chair, 802.3ak
> ======================================
> Principal Engineer, LAN PHY Technology
> System Architect, Workgroup Switching
> dan.dove@hp.com
> hp ProCurve Networking Business
> 8000 Foothills Blvd. MS 5555
> Roseville, CA 95747-5555
> Phone: 916 785 4187
> Fax : 916 785 1815
> ======================================
>
>