A 25 ms burst of noise at a high enough frequency to get out of the radio speaker would sound like a click or pop. A momentary interruption that would be annoying but have no significant impact on information content.
---------- >From: "Chris Maxwell" <[email protected]> >To: <[email protected]>, <[email protected]> >Subject: RE: Company close down due to EMC phenomena >Date: Thu, Jan 17, 2002, 6:18 AM > > > It sounds as though... > > The instantaneous emissions aren't as high as an EFT burst or other type > of transient phenomenon. So, this product causing a hard upset of > electronics is probably not a problem. > > When the conducted emissions limits were set, they were mostly dealing > with whether the product would interfere with radio or TV. As a matter > of fact, the quasi-peak and average detectors are used in order to > simulate the response of the human ear. > > I'm curious. If you set this product right next to a radio. Would a > human being even be able to perceive the 25millisecond burst? > > Chris Maxwell | Design Engineer - Optical Division > email [email protected] | dir +1 315 266 5128 | fax +1 315 797 > 8024 > > NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA > web www.nettest.com | tel +1 315 797 4449 | > > > > >> -----Original Message----- >> From: [email protected] [SMTP:[email protected]] >> Sent: Wednesday, January 16, 2002 3:17 PM >> To: [email protected] >> Subject: Company close down due to EMC phenomena >> >> >> Well, this might be the reality in a case I have been introduced to >> lately. >> >> Case: >> A company are manufacturing PowerLine Communication products. They >> communicate via the power lines and a typical link is between a >> consumer >> residence and the nearest power station. The products can of course >> also >> communicate inside the consumers residence. The communication protocol >> is >> called CEBus http://www.cebus.org/which and make use of the frequency >> band >> 100kHz-400kHz and the amplitude is approximate 2-5V. A typical length >> of a >> transmission is 25ms and occurs approximate one time pr hour. >> >> First of all, AFAIK PowerLine Communication and PowerLine Transmission >> (broadband 1.6MHz-30MHz) are now coming will full force in EU and >> CENELEC/ETSI are working together regulate this type of transmission >> path >> and also coming up with standards. >> >> The problem for the manufacturer is the conducted emission >> requirements in >> EU. According to the EN55022B levels the maximum quasi-peak emission >> is >> 66dBuV@150kHz, and a typical PLC (under transmission) which has been >> measured, showed the value of 120dBuV (peak). With no transmission it >> had a >> margin of 10dB (quasi-peak) and 30dB (average). The radiated emission >> had a >> margin of 10dB. >> >> Well, conducted emission is the problem when transmitting. But, as I >> said, >> the transmission occurs only 25ms/hour. >> >> The national authority will not allowed this product to be placed into >> the >> marked because it do not fulfil the EN55022B limits (100kHz-400kHz) >> under >> transmission mode. No way. >> >> Other national authorities have other approaches on this case, they >> say " as >> long as you do not disturb other equipment, install it. If you do >> disturb, >> we will come and remove it". They also say " install it even if it >> does not >> fulfil EN550022B, but we will remove it if it disturb others". >> >> Two completely different approaches as you see. >> >> Questions: >> 1. Is it possible to have different approaches within EU ? >> 2. Since PLC/PLT is "quite new" technology and since we do not have >> any EU >> product standard (no standard for whose who are using 100kHz-400kHz >> band), I >> like the approach "as long as you do not disturb other equipment, >> install >> it. If you do disturb, we will come and remove it". What is your >> opinion >> about this? >> 3. The transmission occurs very seldom. 25ms/hour, that is 7e-6 and >> approximate 0,001% transmission rate. Can this seldom transmission >> rate be >> an argument to not test the PLC product under continuous transmission >> ? I >> would say yes, but which rate is acceptable / reasonable ? >> >> So, why should the company close down ? Because if the national >> authority >> gets what they want, there will be one sale. Logical, but is it a >> correct >> prohibition the authority call? >> >> >> Best regards >> Amund Westin, Oslo/Norway >> >> >> >> >> >> >> >> ------------------------------------------- >> 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: >> Michael Garretson: [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: >> No longer online until our new server is brought online and the >> old messages are imported into the new server. > > ------------------------------------------- > 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: > Michael Garretson: [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: > No longer online until our new server is brought online and the old > messages are imported into the new server. > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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