Hi Everyone, I just posted my latest Technical Tidbit a few hours ago using a class D stereo amplifier to illustrate a potential problem whereby emission test standards may understate the emissions from a digital device. Here goes: Abstract: Radiated emissions measurements of table top equipment are usually made with the equipment placed on a non-conductive table. But such equipment is often used on conductive surfaces, like a metal desk, and can couple to the conductive surface to enhance emissions, essentially turning the conductive surface into part of an antenna structure. When this happens, standard testing of emissions can understate actual emissions. A Class D (actually labeled Class Z) stereo amplifier is used to illustrate this effect by measuring common mode current on its cables. Link to the article: http://www.emcesd.com/tt2014/tt060114.htm Link to the whole site: http://www.emcesd.com (lots of new stuff) The class D amplifier I used to generate the data is a 20 Watt/channel stereo amp with preamp built-in, a Lepai LP-2020A+. It is a great little amp, if not a little noisy EMC wise, and makes a great EMC demo for those of you who run courses. I tried one at home and cannot tell the difference between it and a much larger amplifier. I plan to give one of these to all attendees in my public seminars. Doug -- University of Oxford Tutor Department for Continuing Education Oxford, Oxfordshire, United Kingdom -------------------------------------------------------------- ___ _ Doug Smith \ / ) P.O. Box 60941 ========= Boulder City, NV 89006-0941 _ / \ / \ _ TEL/FAX: 702-570-6108/570-6013 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-----( ) | o | Email: d...@dsmith.org \ _ / ] \ _ / Web: http://www.dsmith.org -------------------------------------------------------------- - |
- [PSES] radiated emissions tes... Douglas Smith
- Re: [PSES] radiated emis... John Woodgate
- Re: [PSES] radiated emis... ce-test, qualified testing bv - Gert Gremmen
- Re: [PSES] radiated emis... Pettit, Ghery
- Re: [PSES] radiated ... Mike Violette
- Re: [PSES] radia... Richard Nute
- Re: [PSES] r... Charlie Blackham
- Re: [PSES] r... Rick Busche
- Re: [PS... Pettit, Ghery
- Re: [PS... John Woodgate
- Re:... McDiarmid, Ralph