Cam: How did you test it? What were you testing for?
Twisted pairs are good for reducing interference from other sources. They are less effective at reducing interference emitted by your device. The principle is that EM fields fluxing through the loop area formed by your signal conductors generates currents (interference) in your signal conductors. By reducing the loop area you can reduce the interference. But the loop area cannot be reduced to zero, so there will always be some interference. To reduce interference even further, twist the conductors around each other. What this does is make the EM flux currents cancel, since the flux current going through one twist of the loop cancels the flux current going through the adjacent loop. This is why twisted pair is used by 10/100baseT ethernet. You can run 300 ft. ethernet drops of CAT5 and still get good signal integrity, even with all the trash in the EM spectrum (and getting trashier every day). On a PCB, you would have to use vias for your loop crossovers. You would also need to make sure the lengths of each track segment are identical, since symmetry is vital to make the concept work. And put the traces as close together as possible and still be manufacturable. If you are also trying to achieve a tightly controlled impedance, that would be tricky... Best regards, Ivan Baggett Bagotronix Inc. website: www.bagotronix.com ----- Original Message ----- From: "Cam Andruik" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, September 16, 2002 12:47 PM Subject: [PEDA] Twisted-pair tracks > Has anyone ever tried to fake creating a twisted-pair on a PCB? I tried > doing so on a recent board and our testing indicates that it did nothing. I > think it is a waste of time to even attempt it but some people here think it > is helpful. > Thanks for any input, > Cam Andruik > Harding Instruments * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
