The issue as I understand it is that susceptibilities are found during a 61000-4-3 sweep, but cannot be found during a manual scan, or a manual search for a threshold of susceptibility.
I suggest that at the levels at which testing is performed (1, 3 or 10 V/m unmodulated), the threat simulated is a broadcast transmitter and that is a fixed frequency in the commercial world. I don't think immunity to a frequency hopper was contemplated. So outside of the FM broadcast band there should be little concern with FM susceptibility. In fact, the characteristics of the FM band and an automated scan are quite different. A maximum FM deviation is a few tens of kilohertz, whereas, in the FM band a 1% frequency step represents a 1 MHz "deviation." So it seems to me that if an automated sweep repeatedly causes a susceptibility, but a manual attempt to quantify the threshold of susceptibility fails to find it, the test sample should not be considered susceptible. 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 [email protected] 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: Scott Douglas [email protected] Mike Cantwell [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://www.ieeecommunities.org/emc-pstc
