Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: [BP] channels to test our spec.



Joe,

Having spent the better part looking at that channel in relation to the previous channels as well as the newer channels that Charles provided, and this channel has some unique return loss characteristics.  And when I say that, you need to realize that this channel is not symmetrical and SDD11 is significantly different than SDD22.  This channel is the worst in terms of return loss of anything I have really seen, especially interesting is the low frequency return loss.   Also, I noticed that the behavior of the reflections on this channel is higher in amplitude based on the SDD11 and if you look at the pulse response of the forward channel response is different in overall behavior.

 

So, I would say this channel is proof that we do need to add the return loss specification and that our theory that we were capturing all of this in the forward response mask set was probably not 100% correct.

 

John

 

-----Original Message-----
From: Joe M Abler [mailto:abler@US.IBM.COM]
Sent: Tuesday, February 28, 2006 7:05 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] channels to test our spec.

 


Charles,
I ran these channels with the basic sig adhoc setup but with TJ=0.28UI and DCD=3.125%.  I used a PRBS15 data pattern (which is what we defined for the sig adhoc setup) and simulated for 1M bit times.  These were through-channel sims only, no crosstalk applied.  The performance of all channels were considerably better than the thru_worstcase channel.  The lowest performing channel was m82ripple90 with 18% opening at E-12.  

I was surprised at the difference compared to thru_worstcase, which had an eye which was just closed at E-12.  One difference in the previous sim is that I used PRBS23 (since that's what is defined for EIT) and simulated for 10M bits.  I reran the channel using PRBS15 & 1M bits, which resulted in about an 8% eye at E-12.  So there is a fair impact from PRBS23, but this channel is still significantly worse than the others.  

Bottom line is that I'm not finding anything with these new channels that would provide insight on how to redraw the line.


Thanks,        Joe


Joe Abler                                                             abler@us.ibm.com
IBM Systems & Technology Group            919-254-0573
High Speed Serial Link Solutions               919-254-9616 (fax)
3039 Cornwallis Road                                                                
Research Triangle Park, NC  27709


 

Charles Moore <charles.moore@AVAGOTECH.COM>

02/22/2006 07:41 PM
Please respond to Charles Moore

       
        To:        STDS-802-3-BLADE@listserv.ieee.org
        cc:        
        Subject:        [BP] channels to test our spec.




joe, et al,

Here are some channels to look at the ripple vs attenuation
problem.

charles
--
|--------------------------------------------------------------------|
|       Charles Moore
|       Avago Technologies
|       ISD
|       charles.moore@avagotech.com
|       (970) 288-4561
|--------------------------------------------------------------------|




#### constructedChannels1.zip has been removed from this note on February 28, 2006 by Joe M Abler