I don't know what would cause a 30 dB variation, but a standard source could be several things. MIL-STD-461E requires proving the measurement system integrity by injecting a known signal between the LISN power output connector and LISN chassis and measuring it off the LISN port. Here an rf signal source and oscilloscope are all that are necessary. If you don't have an rf signal source, an audio source might get you up just above 150 kHz, which is in the LISN frequency range. If your spectrum analyzer has a cal output that is within the calibrated region of your LISN impedance (<30 MHz) that will do as well. In a pinch you could build a pulse generator out of a 555 timer (or better yet a 74121/74123 one shot/dual one shot) and look at its spectral content with your analyzer, then drive the LISN with that.
> From: "Gordon,Ian" <[email protected]> > Reply-To: "Gordon,Ian" <[email protected]> > Date: Mon, 11 Aug 2003 16:32:46 +0100 > To: "'IEEE EMC-PSTC GROUP'" <[email protected]> > Subject: Temperature effects on conducted emissions? > > > All > Can anyone suggest a means by which the indicated signal from a LISN + > transient limiter + receiver combination can result in a 30dB change over > one month? I used the same "reference source" and test configuration on both > occasions to generate emissions. However, the source is merely a piece of > standard equipment and not intended as a calibration reference. > The temperature has varied considerably over the last month but I would not > have thought this could result in a 30dB variation. > Alternatively, can anyone suggest a means of constructing a reference source > which may be connected to the LISN input? > Thanks > Ian Gordon > > _____________________________________________________________________ > This e-mail has been scanned for viruses by MCI's Internet Managed Scanning > Services - powered by MessageLabs. For further information visit > http://www.mci.com > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > Archive is being moved, we will announce when it is back on-line. > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
