You might want to attend my archived NetSeminar "Shortening the = development with effective eye measurements" at www.netseminar.com. It = was presented on April 16, 2002. Pretty basic but covers a lot of topics = relevant to eye diagram measurements. =20 Art Porter =20 -----Original Message----- From: San Miguel, Shane [mailto:shane.san.miguel@xxxxxxxxx] Sent: Monday, September 29, 2003 9:41 AM To: kbagga31@xxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: eye diagram An eye diagram shows you how sloppy you can be :) =3D20 The "eye" is the boundary that a signal may vary in amplitude and time = =3D with reference to another signal while maintaining a passing test =3D condition. If a signal is supposed to be aligned with clock, it has a = =3D spec that says it can vary +- some given time amount (can be thought of = =3D as something like jitter) around this reference and still be valid. The = =3D voltage level that this signal rides at (usually Vtt or Vref) can also = =3D vary a +- amount around it's level. If you combine the +- voltage =3D variance and the +- time variance you end up with something the shape of = =3D an eye. In the broadest generalization, the more "eye" you have, the = =3D more margin-to-fail you have. The example I give is using spec values but in practice, you vary the = =3D voltage and timing to push the device until failure thus defining the = =3D eye. Shane San Miguel=3D20 Senior Product Engineer=3D20 Platform Memory Operations=3D20 Intel Corporation=3D20 =3D20 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of karan bagga Sent: Monday, September 29, 2003 1:37 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] eye diagram Hi, =3D20 Want to know about eye diagram. How does eye diagram plays a role in desiging Multi Gigaherts PCBs ? What is the methodology i.e do eye diagrams come in datasheets. Need some basic understanding on relation with eye diagram and SI. =3D20 Regards Karan --------------------------------- Do you Yahoo!? The New Yahoo! Shopping - with improved product search ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: =3D20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=3D20 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=20 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //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