Lots of good advice so far. The prescan is simply to find the frequencies of interest. Once found, then you must dwell at each frequency and maximize the signal by turntable position and antenna height. You also need to spend some effort moving the EUT cables, if applicable. What I have not seen mentioned so far is that each compliance measurement, after all the above is completed, MUST be made in a non-frequency swept mode (zero span) and dwell for at least 15 seconds. (CISPR 16-2-2 section 8.5). Bob Richards, NCT.
--- On Thu, 12/4/08, Luke Turnbull <[email protected]> wrote: > From: Luke Turnbull <[email protected]> > Subject: Re: Radiated emission - time at each frequency > To: [email protected], "Amund Westin" <[email protected]> > Date: Thursday, December 4, 2008, 3:07 PM > Amund, > > What you need to do is to split the band into 100 MHz > segments. In each segment, use a "fast scan" on a > spectrum analyser in peak detector mode. The sweep time > should the minimum possible - approx 100 ms (which probably > means the sweep-and-flyback time is less than 150 ms). Use > Max Hold and dwell for several minutes in this band. Select > frequencies of interest and then re-measure these with a QP > detector over several minutes each. > > This approach guarantees that you will not miss any events > that are longer than the peak-and-flyback time that happen > within the time that you wait for each Max Hold segment. > > If there are any intermittent events shorter than the > peak-and-flyback time, they will probably be insignificant > when measured with a QP detector anyway. (And CISPR 14 > disregards clicks shorter than 200 ms anyway). > > Best Regards, > > Luke Turnbull > > > Dr Luke Turnbull > EMC Technical Manager > TRW Conekt > Stratford Road > Solihull > West Midlands B90 4GW > > Tel: +44 (0)121.627.3966 > Mobile: +44 (0)7730.671284 > Fax: +44 (0)121.627.4353 > > email: [email protected] > web: www.conekt.net > > - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/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: Jim Bacher <[email protected]> David Heald <[email protected]>
