The answers to this question, or similar questions in the general areas of jitter, noise, and signal integrity (Xtalk included) can be found in a= recent publication by Prentice Hall entitled "Jitter, Noise, and Signal = Integrity at High Speed" at=20 http://www.amazon.com/Jitter-Integrity-High-Speed-Prentice-Semiconductor/= dp/0132429616 with ISBN-13: 978-0-13-242961-0 ISBN-10: 0-13-242961-6 Thanks! Mike =20 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of xuzhengrong Sent: Sunday, December 02, 2007 6:10 PM To: shawn.h.zheng@xxxxxxxxx Cc: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] =B4=F0=B8=B4: Xtalk from vertical via to horizontal tr= ace From some paper I also learnt that parallel-plated waveguide (PPW) noise = =3D can be excited from vias in PCBs due to the mode conversion. The excited PPW noise can propagate through a PPW composed of power and ground planes. =3D= The propagation of the PPW noise through PCBs results in resonances in transmission characteristics of signal vias due to the multiple =3D reflections from the edge of PCBs and coupling between signal vias.=3D20 I wonder how much xtalk the propagation of noise through via to via and =3D= via to trace results in, too. Appreciate for any ideas. Best Regards, Zhengrong -----=3DD3=3DCA=3DBC=3DFE=3DD4=3DAD=3DBC=3DFE----- =3DB7=3DA2=3DBC=3DFE=3DC8=3DCB: si-list-bounce@xxxxxxxxxxxxx =3D [mailto:si-list-bounce@xxxxxxxxxxxxx] =3DB4=3DFA=3DB1=3DED Shawn Zheng =3DB7=3DA2=3DCB=3DCD=3DCA=3DB1=3DBC=3DE4: 2007=3DC4=3DEA12=3DD4=3DC22=3DC= 8=3DD5 22:07 =3DCA=3DD5=3DBC=3DFE=3DC8=3DCB: si-list@xxxxxxxxxxxxx =3DD6=3DF7=3DCC=3DE2: [SI-LIST] Xtalk from vertical via to horizontal tra= ce Hi, I appreciate if you care to offer your help on the following two xtalk scenarios 1. xtalk from vertical via to horizontal trace via --| ----------------------------------------pwr | | | | ----------------------trace | --|------------------------------------gnd | -------------- Only read some literature that talk about via to via coupling. I wonder =3D= how much direct coupling is from vertical via to horizontal trace is. I =3D think it is minimum since the trace is close to the ground. Let us think =3D differently. It is well known that the current transition through via cause voltage =3D= diff between parallel planes (pwr and gnd) fluctuates. Does the fluctuation =3D= then impact signal on the trace? 2. pwr reference impact on signal ----------------------------------------pwr ----------------------trace --------------------------------------gnd If power plane above trace is noisy but stays larger distance to trace =3D= than ground plane, how much does the power plane affect trace reference to ground? Kind of similar to the first question above. Thanks. 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