In article <bdcbdbe5.19b9d%ken.ja...@emccompliance.com>, Ken Javor <ken.ja...@emccompliance.com> writes >I made some AM band measurements, peak detection: > >Freq Ampl. >MHz dBuV >0.45 98 >0.55 94 >0.63 92 >0.75 90 >0.83 86 >0.88 83 >0.94 82 >1 78 >1.2 73 >1.4 72 >1.54 70 >1.61 68 >1.68 67 >1.73 69 > >These were rectification harmonics. If I turned on video averaging, >they went away and left a nice spectrum of some cw switching activity at >a much lower level. It is the rectification harmonics, not the >switcher, that causes the problem. BTW, the noise was pure differential >mode - there was no common mode component, which is to be expected for >this two wire topology.
I suppose these are conducted emissions, measured according to CISPR 15. But these lamps are subject only to the 'insertion loss' measurement described in clause 7. Someone has left out the capacitors across the rectifier diodes, or used cheap diodes instead of the special ones that don't produce as much r.f. -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Scott Douglas emcp...@ptcnh.net 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://www.ieeecommunities.org/emc-pstc
