Re: VSWR FROM ATTACHED DATA
I read in !emc-pstc that Price, Ed ed.pr...@cubic.com wrote (in b78135310217d511907c0090273f5190d0b...@curly.ds.cubic.com) about 'VSWR FROM ATTACHED DATA' on Tue, 29 Oct 2002: Ohms (output port shorted or open). Now, I'll assume that the driving RF generator had a source impedance of 50 Ohms. First, you can find the reflection coefficient, r, from: r = [(Zl - Zo)/(Zl + Zo)] Where the source impedance, Zo, is 50 Ohms, and the load impedance (the CDN reported data) is 130 Ohms, then: r = 0. Then, you can find the VSWR from: VSWR = [(1 + r)/(1 - r)] So, the VSWR at 150 kHz is 2.6! All that should be explained in your lab's #2108 Test Procedure. Well, it may be, but I hope that it might adopt a simpler approach. Your two equations appear to lead, after a small amount of algebra, to VSWR = Z1/Zo, and that is consistent with your numerical result. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- 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
RE: VSWR FROM ATTACHED DATA
-Original Message- From: Gordon,Ian [mailto:ian.gor...@edwards.boc.com] Sent: Tuesday, October 29, 2002 3:25 AM To: 'IEEE EMC SAFETY PSTC' Subject: VSWR FROM ATTACHED DATA People You may remember that you helped me a few weeks ago with VRC/VSWR assessments. As part of the same work I am attempting to assign a VRC/VSWR for a coupling de-coupling device (CDN) but have not been able to get a typical value from the manufacturer of the device. However, I have been sent the attached data. Are you able to help again by telling me how to calculate the VSWR or VRC from this data? Thanks Ian Gordon Ian: You could calculate the VSWR in two step from the data you have. For instance, at 150 kHz, the reported input impedance of the CDN was about 130 Ohms (output port shorted or open). Now, I'll assume that the driving RF generator had a source impedance of 50 Ohms. First, you can find the reflection coefficient, r, from: r = [(Zl - Zo)/(Zl + Zo)] Where the source impedance, Zo, is 50 Ohms, and the load impedance (the CDN reported data) is 130 Ohms, then: r = 0. Then, you can find the VSWR from: VSWR = [(1 + r)/(1 - r)] So, the VSWR at 150 kHz is 2.6! All that should be explained in your lab's #2108 Test Procedure. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- 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
