*From*: "Townsend, Fred" <ftownsend@xxxxxxxxxxxx>*To*: <David.Carney@xxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>*Date*: Thu, 26 Jul 2007 09:04:32 -0700

David: I have to ask what would be gained from such a topology? Ron and Scott both make some very good points. In the case of the Mux bus (1553)the ring encompasses the airplane and the double ring structure gives increased reliability. Microwave can make use of some structures like directional couplers to help reduce reflections. If rings are good why aren't we still using the token ring? Again the token ring was over an area much bigger than a PCB. A ring in a PCB would have all of the problems with no apparent gain. Think about your PCB router. Rings would drive the router nuts? Fred Townsend -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of David Carney (Neenah) Sent: Thursday, July 26, 2007 6:47 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Circle bus topology Has anyone ever experimented with a circle bus topology. The basic concept would be a bus with several devices attached. They would be routed in a daisy chain topology, and then the two ends of the daisy chain would be connected together. The PCB routing would look like a circle or a loop for each net on the bus. Pointers to references such as papers or application notes would be greatly appreciated. I'm particularly interested in signal integrity and EMC implications of this topology. =20 Thanks. =20 =20 ---------- David Carney Senior Hardware Engineer Plexus Corp. Phone - 920-751-5646 =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 technical documents are available at: http://www.si-list.net 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 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 technical documents are available at: http://www.si-list.net 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

**Follow-Ups**:**[SI-LIST] Re: Circle bus topology; Circular Firing Squad?***From:*Salkow, Steven

**References**:**[SI-LIST] Circle bus topology***From:*David Carney \(Neenah\)

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