Re: ISM prohibited frequencies
Jeff For FCC purposes, operation implies an emission intentionally generated for the purposes of communication of information, or in Part 18 for the purpose of generating heat, plasma, etc. Harmonics, spurs, and other undesired consequences of the generation/modulation process are not considered to be operating frequencies. The same would apply to internally generated signals (eg, local oscillators, cpu clocks, PLL references, etc). The limits specified in 18.305b limit the radiated emissions levels of these undesired or unneeded radio frequency emissions . The operating frequency definition questions came up not long ago in reference to the proposed ultra-wide band transmitters rules for Part 15 operation. The thinking there was if your UWB signal was partly in a restricted band, and if filtering it out would degrade the information being transmitted or would otherwise compromise the transmission link, then your emission there was an operating frequency, and would not be allowed. If however the emission there were a true spur or harmonic, eliminating this energy would not compromise the communications link, and the emission could be evaluated against the appropriate limit for unwanted emission. Hope this helps. Best regards Tom Cokenias T.N. Cokenias Consulting P.O. Box 1086 El Granada CA 94018 tel 650 726 1263fax 650 726 1252 page 800 759 pin 630 2820 At 8:37 AM -0600 5/24/00, JENKINS, JEFF wrote: I have a question about ISM prohibited frequencies according to 47 CFR Part 18. Section 18.303 says that operation in the prohibited frequency bands is not allowed. My question is, what is their interpretation of the word operation? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: ISM prohibited frequencies
Hello Jenkins, As long as the levels in the restricted bands are below the limits specified in 15.209, you should be okay. No frequency (fundamental or harmonic or 'internal functioning') within a restricted band can exceed the levels specified in 15.209. Regards, Bandele Jetstream Communications, Inc. badep...@jetstream.com -Original Message- From: JENKINS, JEFF [mailto:jeff.jenk...@aei.com] Sent: Wednesday, May 24, 2000 7:38 AM To: emc-p...@majordomo.ieee.org Subject: ISM prohibited frequencies I have a question about ISM prohibited frequencies according to 47 CFR Part 18. Section 18.303 says that operation in the prohibited frequency bands is not allowed. My question is, what is their interpretation of the word operation? 1.) If the equipment in question uses these frequencies only for internal functioning, is it still prohibited? (In other words, the energy does not intentionally leave the equipment enclosure.) 2.) If the equipment sweeps through a prohibited band while it auto-tunes, is this a problem? 3.) What if the fundamental operating frequency of the equipment is outside the prohibited bands, but there is significant harmonic energy within a prohibited band? Thanks, Jeff Jenkins Regulatory Compliance Advanced Energy Industries, Inc. Fort Collins, CO USA --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: ISM prohibited frequencies
I asked the same questions of the FCC a couple of years ago and was told (reply your Q): (2)The sweep-through wasn't necessarily a problem if powered operation was not possible within the prohibited bands. (3)Harmonics...(partly my interpretation)then you are responsible to assure that emissions are 10uV/m @ 1600m for these emissions (1) internal (entirely my own...) The FCC are concerned with interference with emergency/rescue services; if your oscillators' signals are contained, there can be no interference. HTH --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
