*From*: "Loyer, Jeff" <jeff.loyer@xxxxxxxxx>*To*: <Chris.Cheng@xxxxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>*Date*: Wed, 18 May 2005 07:53:24 -0700

Funny - I was going to post something similar. My additional comments would be (referncing your numbering scheme): 3a) For simple differential structures, you might not only be able to invoke symmetry about the horizontal axis, but also the vertical axis, allowing injecting into a single port (never having to move the stimulus). 4a, 5a) IConnect's TDA does this nicely. Error correction is a lot less involved than in the frequency domain (this has intrigued me for a while - why can we correct wonderfully with a single "thru" in the time domain, but need several "lines" for a TRL in the frequency domain?). Replies to your questions: a) yep - it can be done b & c) one of the challenges will be to make sure your 2 receiver channels are aligned, else you might end up with bogus (non-passive) results. One of the nice things about the time domain is that you can look at your 4-port data and make sure it "makes sense" before going through the exercise of converting to S-parameters, etc. =20 For instance, does your T41 pulse occur before T21? If so, you probably induced an error somehow. You'll especially want to compare T11 and T31 waveforms - these would give the clearest indication that you had erroneous skew between your receiver channels. P1 ------ P2 P3 ------ P4 Jeff Loyer -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Chris Cheng Sent: Tuesday, May 17, 2005 1:22 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Estimate ISI with S parameters -- Using TDR to do SDD21 correlation? I have to admit I've never try this before but I am about to give it a = =3D shot myself so tell me I am crazy or worst trying. 1) If you have a TDR head, you should be able to do single ended TDR and TDT. 2) If you treat your differential lines as 4 ports, you can measure TDRxy and TDTxy on sequential pairs of ports while terminating the =3D other 2 ports with 50 ohm terminators.=3D20 3) If you invoke symmetry on the lines you just need to measure the upper or lower diagonal of the matrix. 4) Do your FFT to transform the TDT/TDR to single ended Sxy parameters 5) Clean them up with your favorite SOLT error corrections methods 6) Transform the Sxy matrix into mix mode Sddcc matrix. My questions are : a) Can this be done ? b) How "clean" do I need on the SOLT error corrections ? Can it be skipped ? c) Do I have to worry about passivity on these extracted parameters ? -----Original Message----- From: John@xxxxxxxxxxxx [mailto:John@xxxxxxxxxxxx] Sent: Monday, May 16, 2005 7:13 PM To: Scott McMorrow Cc: steve weir; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Estimate ISI with S parameters -- Using TDR to do =3D SDD21 correlation? Hi Scott, =3D20 Thank you for helps. Yes, I can run circuit with s-parameter model. Here, one question. =3D Before, I would like to run random pattern for ISI. Recently studying, show = =3D only need to do pulse response to see how the result waveform penetrates to next signal. It makes sense to me =3D and also easier to run simulation. Any comments on this method? =3D20 Also, I don't have a 4 port VNA to measurement SDD21 for correlation. However I have a TDR with only one differential module to measure trace impedance (SDD11).=3D20 (I cannot use TDT functions since only one module installed) =3D20 Is it reasonable to correlate SDD11 as a indicator for the correlation = =3D of SDD21? Do I miss something? =3D20 Thanks, John =3D20 =3D20 =3D20 ________________________________ From: Scott McMorrow [mailto:scott@xxxxxxxxxxxxx]=3D20 Sent: Monday, May 16, 2005 9:21 PM To: John Lin (=3DAAL=3DB4=3DC2=3DB7=3DD7) Cc: steve weir; si-list@xxxxxxxxxxxxx Subject: Re: [SI-LIST] Re: Estimate ISI with S parameters? John If you have HSPICE available, you can set up a circuit with s-parameter modeling to measure any pattern dependent ISI that you want. scott Scott McMorrow Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 (401) 284-1827 Business (401) 284-1840 Fax http://www.teraspeed.com Teraspeed(r) is the registered service mark of Teraspeed Consulting Group LLC John Lin (=3DAAL=3DB4=3DC2=3DB7=3DD7) wrote:=3D20 Hi Steve, =3D09 Thanks for your helps. =3D09 >From other response, it looks like, I need to transfer channel's S =3D3D parameters into time domain and do pulse repsonse to see how the curve at the falling edge =3D3D penetrates to the period=3D3D20 Of a next signal. =3D09 In your mail, ISI is relative to attenuation,SDD21. =3D09 I read SAS/SATA spec. There is a ISI compliant curve shown on a SDD21 =3D3D chart.=3D3D20 The ISI curve is steeper than SDD21 compliant curve.=3D3D20 =3D09 How to generate a ISI curve at the frequency domain by simulation to =3D3D check if meet the requirement.? =3D09 Thanks, John =3D09 =3D09 =3D09 =3D09 -----Original Message----- From: steve weir [mailto:weirsi@xxxxxxxxxx]=3D3D20 Sent: Saturday, May 14, 2005 1:34 AM To: John Lin (=3D3DAAL=3D3DB4=3D3DC2=3D3DB7=3D3DD7); = si-list@xxxxxxxxxxxxx Cc: John Lin (=3D3DAAL=3D3DB4=3D3DC2=3D3DB7=3D3DD7) Subject: Re: [SI-LIST] Estimate ISI with S parameters? =3D09 John variable attenuation versus frequency within the symbol frequency =3D3D band will give rise to ISI as the amplitude at any given point will =3D3D depend on the previous history of symbols, and hence the name ISI. =3D09 Steve At 10:25 AM 5/13/2005 +0800, =3D3D3D?big5?B?Sm9obiBMaW4gKKpMtMK31yk=3D3D3D?=3D3D3D =3D3D wrote: =3D20 Dear all SI experts, =3D09 Can some ones explain how to relate ISI (inter-symbol interference) to=3D3D20 S parameters? =3D09 What can be observed from S -parameter for differential 4 parts=3D3D20 simulation? For example, crosstalk, attenuation, reflection,....etc. =3D09 Thanks, John =3D09 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field =3D09 or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list =3D09 For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field =3D09 List FAQ wiki page is located at: =09 http://si-list.org/wiki/wiki.pl?Si-List_FAQ =3D09 List technical documents are available at: http://www.si-list.org =3D09 List archives are viewable at: =09 http://www.freelists.org/archives/si-list or at our remote archives: =3D09 http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =3D09 =3D20 =3D09 =09 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field =3D09 or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list =3D09 For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field =3D09 List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ =3D09 List technical documents are available at: http://www.si-list.org =3D09 List archives are viewable at: =3D20 http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =3D20 =3D09 =3D09 =3D20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: =3D20 http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =3D20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: =20 http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu

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