This may not be the effect being referred to, but... Relays require a ferromagnetic alloy, such as Kovar for the contacts. The leads leading to the connector are more likely beryllium copper or some similar material. The weld or joint between them forms a thermoelectrically active junction, and an associated error potential.
Ideally, the two contacts form two sets of junctions that are opposite in polarity. In reality, they are seldom identically constructed, and if there's a temperature gradient across the part the error is magnified. Perhaps this was an effort to stress that the signal amplitude should be in excess of the thermoelectric offsets. Another possibility -- Many small form-factor relays are the reed type, so wiping action across the contacts forms a conduction path. There may be a minute oxide layer there or elsewhere in the system which will create the non-linear behavior described. Point contact rectification and dielectric breakdown become possibilities. Probably not pertinent, but interesting. Timothy J. Christman Test Engineer Tel 651.582.3141 Fax 651.582.7599 timothy.christ...@guidant.com Guidant Corporation 4100 Hamline Ave. N. St. Paul, MN 55112 USA www.guidant.com -----Original Message----- From: Robert Wilson [mailto:robert_wil...@tirsys.com] Sent: Thursday, May 23, 2002 6:32 PM To: emc-p...@majordomo.ieee.org Subject: RE: Coaxial Switches - use with spectrum analyzer and gear? As it is stated, below -20dB, nothing at all comes through the switch. Then once you reach that level, output signal level suddenly begins increasing from zero. That obviously makes no sense and is probably only a result of an engineering spec being lost in translation when Marketing created the Data Sheet. Losses are not an offset that must be overcome before any output is generated, but simply as Ken mentioned, a proportion of input power. Bob Wilson TIR Systems Ltd. Vancouver. -----Original Message----- From: richwo...@tycoint.com [mailto:richwo...@tycoint.com] Sent: May 23, 2002 1:37 PM To: emc-p...@majordomo.ieee.org Subject: RE: Coaxial Switches - use with spectrum analyzer and gear? That information is from an application document found on the Dow Key web site. I can't say that I fully understand it myself. Richard Woods Sensormatic Electronics Tyco International -----Original Message----- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, May 23, 2002 3:59 PM To: richwo...@tycoint.com; emc-p...@majordomo.ieee.org Subject: Re: Coaxial Switches - use with spectrum analyzer and gear? I don't understand the snipped statement below. Isn't the loss just a fraction of the power flowing through the switch? ---------- >From: richwo...@tycoint.com >To: emc-p...@majordomo.ieee.org >Subject: RE: Coaxial Switches - use with spectrum analyzer and gear? >Date: Thu, May 23, 2002, 12:22 PM > > A minimum power of about -20dbm must be used to overcome the > losses in the switch. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
