Mike: My experience tells me that an attenuator designed for the same impedance as the transmission line, will **always** improve the VSWR at the source, irrespective of how bad or good the load VSWR is. (It is most helpful to think in terms of reflection coefficients rather than VSWR directly, to appreciate this.) Your comment implies otherwise, and I wonder if you could expand on what you've said - perhaps an example of where it doesn't help (not a given)?
Regards, Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 585 442 3909 Fax: 585 442 2182 [email protected] ----- Original Message ----- From: "Mike Hopkins" <[email protected]> To: "'Colgan, Chris'" <[email protected]>; "EMC Forum" <[email protected]> Sent: Wednesday, February 20, 2002 1:48 PM Subject: RE: EN61000-6-2 | | Seems an attenuator COULD improve matching and VSWR if it then became a | significant part of the load impedance; it isn't a given..... On the other | hand, adding the attenuator should NOT cause the VSWR to become very high | unless it is not a 50 ohm attenuator...... | | Mike Hopkins | | -----Original Message----- | From: Colgan, Chris [mailto:[email protected]] | Sent: Wednesday, February 20, 2002 4:26 AM | To: EMC Forum | Subject: RE: EN61000-6-2 | | | | In my experience attenuators improve impedance matching and hence VSWR. | There must be something wrong with your set up. | | Regards | | Chris Colgan | Compliance Engineer | TAG McLaren Audio Ltd | The Summit, Latham Road | Huntingdon, Cambs, PE29 6ZU | *Tel: +44 (0)1480 415 627 | *Fax: +44 (0)1480 52159 | * Mailto:[email protected] | * http://www.tagmclaren.com | | | > -----Original Message----- | > From: Sam Wismer [SMTP:[email protected]] | > Sent: 19 February 2002 16:52 | > To: EMC Forum | > Subject: EN61000-6-2 | > | > Hi Group, | > | > EN 61000-6-2 calls for severity level 3, or 10Vrms for conducted | > disturbances. This equates to 37dBm which is 7dB higher than the upper | > limit my receiver will handle (during calibration of the CDN). I've tried | > to use an attenuator and compensate for it in my readings, but this | > creates a high VSWR. Any ideas how to extend the dynamic range of my | > receiver without causing high VSWR? | > | > | > | > | > | > Kind Regards, | > | > | > | > | > | > Sam Wismer | > | > Engineering Manager | > | > ACS, Inc. | > | > | > | > Phone: (770) 831-8048 | > | > Fax: (770) 831-8598 | > | > | > | > Web: www.acstestlab.com | > | > | > | | | ************************************************************** | Please visit us at www.tagmclaren.com | ************************************************************** | | The contents of this E-mail are confidential and for the exclusive | use of the intended recipient. If you receive this E-mail in error, | please delete it from your system immediately and notify us either | by E-mail, telephone or fax. You should not copy, forward or | otherwise disclose the content of the E-mail. | | TAG McLaren Audio Ltd | The Summit, 11 Latham Road | Huntingdon, Cambs, PE29 6ZU | Telephone : 01480 415600 (+44 1480 415600) | Facsimile : 01480 52159 (+44 1480 52159) | | ************************************************************** | Please visit us at www.tagmclaren.com | ************************************************************** | | ------------------------------------------- | 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: | [email protected] | with the single line: | unsubscribe emc-pstc | | For help, send mail to the list administrators: | Ron Pickard: [email protected] | Dave Heald: [email protected] | | For policy questions, send mail to: | Richard Nute: [email protected] | Jim Bacher: [email protected] | | 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: | [email protected] | with the single line: | unsubscribe emc-pstc | | For help, send mail to the list administrators: | Ron Pickard: [email protected] | Dave Heald: [email protected] | | For policy questions, send mail to: | Richard Nute: [email protected] | Jim Bacher: [email protected] | | 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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"
