Another thought: One might video average over 2 ms with enough samples OR use a 500 Hz post detection video filter -- but not both together. Cortland KA5S
----- Original Message ----- From: Cortland Richmond <mailto:[email protected]> To: emc-pstc <mailto:[email protected]> Sent: 4/27/2007 10:02:23 AM Subject: Re: FCC R&R Part 25 Ed Price asked: Since the FCC says "eirp" density, the I assume that means that the signal is to be measured as it radiates from the EUT. (The EUT has a separate discrete antenna, connected to the EUT by a length of coax cable.) Am I correct that I can't measure the "eirp" density by looking into the coax cable; that I have to do a measurement of the radiated field? Ed, Reasoning from ignorance here (grin) but if you measure the EUT output emissions, you start with "shall not exceed -80 dBW/MHz in the 15591610 MHz band averaged over any 2 millisecond active transmission interval." Subtracting antenna gain dBi, adding coax and conector losses, you end up with the reqiurement at the antenna port. I'd think you would have to use 1 MHz RBW, peak detection, linear mode, and a video filter setting of (2ms^-1) or 500 Hz to accomplish the 2msec averaging and reference to dB/MHz. ISTR that measurement above 1 GHz have to be made at 1 MHz RBW unless otherwise specified. Cortland Richmond KA5S - ---------------------------------------------------------------- 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/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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ - ---------------------------------------------------------------- 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/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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
