[SI-LIST] Re: return loss of whole channel
- From: John Lin <johnlinc@xxxxxxxxx>
- To: sherman.chen@xxxxxxx
- Date: Tue, 23 Dec 2014 00:36:15 +0800
Hi Sherman,
Check Infiniband, I am sure there is spec for RL. I asked a similar
question previously in SI-List.
You can refer to the archive: "
http://comments.gmane.org/gmane.technology.electronics.signal-integrity/19301
".
Thanks
John Lin
SI/PI simulation design at Lenovo
2014-12-22 22:03 GMT+08:00 Chen, Sherman <sherman.chen@xxxxxxx>:
> Dear si-listers,
> Merry Christmas!
>
> While many of you are inside the holiday aura I wish a little bit
> technical discussion could also become a part of your enjoyment - that's
> what we engineers like, right:)
>
> We are currently investigating an issue which made us think of this
> question "should there be a return loss spec defined for the whole channel"?
>
> I searched some most popular specs and the table below is a summary of the
> RL, IL values in those specs (Comments and corrections are very welcome).
>
> I didn't find the requirement on the whole channel return loss in any of
> them. As we know, given the worst case RL at each test point, and the min
> IL of each segment, the whole channel RL can be readily calculated. Is the
> reason not giving this parameter due to not all segments are well defined
> in whichever of these standard, or there is other reasons preventing from
> doing so?
>
>
>
> PCIe
>
> SAS3
>
> FC-PI-5
> (1600-DF-EL-S)
>
> SATA2
>
> SATA3
>
> Transmitter
>
> 4dB
>
> 7.9dB
>
> 6.4dB
>
> 6dB
>
> 14dB @300MHz
>
> Receiver
>
> 5dB
>
> 7.9dB
>
> 12dB
>
> 8dB
>
> 18dB @300MHz
>
> Calibration channel
>
> 18dB
>
>
>
>
>
>
>
>
>
> Connector
>
>
>
>
>
> 20dB
>
>
>
>
>
> Cable
>
>
>
> 7.9dB
>
>
>
>
>
>
>
> Test load
>
>
>
> 15dB
>
>
>
>
>
>
>
> Max Insertion loss of whole channel
>
> 20+-2dB
>
> 24dB
>
>
>
>
>
>
>
> RL of whole channel
>
>
>
>
>
>
>
>
>
>
>
>
> Notes:
>
> 1. All RL are min values of differential return loss.
>
> 2. The freq. point is the Nyquist freq. unless otherwise indicated.
>
> Best Regards,
>
> Sherman Chen
> Signal Integrity
> EMC Global Hardware Engineering
> Tel: +86 21 60951100-3329
>
>
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