http://www.ieee-pses.org/symposium http://www.emc2004.org/
Typical radio receivers have local oscillators and possibly one or more IF oscillators whose emissions can couple internally to the antenna to be radiated. Or, such signals can be coupled through the DC bus to RF stages with similar consequences. This will occur in an unfortunately efficient manner even if it may be 10.7 MHz or more removed from the intended operating frequencies, or at several harmonics above. Digital system noise can possibly couple into the receiver RF stages as well. Non-Mil limits are common for unwanted receiver emissions, such as those of the FCC. Best Regards, Eric Lifsey Gary McInturff said: > http://www.ieee-pses.org/symposium > http://www.emc2004.org/ > -------------------------------------------------- > > Ed, > Not sure that it really helps but paragraph 50.15 (in > the appendix) > Not sure it helps much but ... "The basic intent is to protect > sensitive > receivers from interference couple through the antennas > associated with the > receiver". One could assume, the want to know what noise is > coming out of > the antenna ports when it is not purposefully transmitting - and > thereby > potentially covering up any unintentional radiated noise just > due to > equipment operating - but not transmitting. Makes better sense > from a > transmitting state than a receiving state, since a receiver is > constantly > "listening". Seems there should be a receiver standby RS test. > Of course the above assumption means that there must be > a RE test > defined for the actual transmitting frequencies and harmonics, > possibly > RS103. > Gary > Wouldn't be the first time I guessed wrong. > > -----Original Message----- > From: Price, Ed [mailto:[email protected]] > Sent: Monday, July 12, 2004 7:55 AM > To: '[email protected]' > Subject: MIL-STD-461E Method RE102 Applicability > > > http://www.ieee-pses.org/symposium > http://www.emc2004.org/ > -------------------------------------------------- > > And now for something completely different, a question on the > applicability > of Method RE102. > > Paragraph 5.16.1, RE102 Applicability, reads: > > "This requirement is applicable for radiated emissions from > equipment and > subsystem enclosures, all interconnecting cables, and antennas > designed to > be permanently mounted to the EUTs (receivers and transmitters > in standby > mode)." > > I normally test a transmitter by operating it, with modulation, > into a dummy > load placed directly onto its RF output port. My rationale is > that the > transmitter and modulator circuits will load the power supply, > and exercise > data paths, that could well cause emissions at frequencies far > removed from > the fundamental. > > So what is that parenthetical phrase trying to say? The more I > stare at it, > the more I want to reach for an eraser. > > Regards, > > Ed > > > Ed Price > [email protected] WB6WSN > NARTE Certified EMC Engineer & Technician > Electromagnetic Compatibility Lab > Cubic Defense Applications > San Diego, CA USA > 858-505-2780 (Voice) > 858-505-1583 (Fax) > Military & Avionics EMC Is Our Specialty > This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. IEEE PSES Main Website: http://www.ieee-pses.org/ To post a message send your e-mail to [email protected] Instructions for use of the list server: 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: [email protected] Dave Heald: [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
