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Topic: Radio frequency interference

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	eEngineer -- Radio Frequency Interference (RFI)
		This is defined as undesired signals with frequency components that fall within the receiver’s RF passband and are translated into the Intermediate Frequency (IF) passband via the mixer stage.
		This is defined as undesired signals with frequency components which fall within or near the receiver’s RF passband and are translated outside of the IF passband via the mixer stage.
		This is defined as undesired signals with frequency components that are significantly removed from the receiver’s RF passband.
	www.radioing.com /eengineer/rfi.html (931 words)

	Emergency radio frequency warning device - Patent 3949300
		The radio frequency safety device of claim 6 further comprising a bandpass shaping filter for limiting the bandwidth of the output of said signal generator to substantially the AM and FM broadcast bands.
		The radio frequency safety device of claim 8 wherein said carrier signal has a frequency lower than the lowest frequency in the FM broadcast band and wherein said audio signal is a representation of an audible warning signal.
		Radio receivers in the vehicles located in the vicinity of the transmitter detect the modulated noise signal and the received signal accordingly interferes with the station or channel being received by the vehicle radio.
	www.freepatentsonline.com /3949300.html (1552 words)

	Radio Frequency Interference
		This is a narrowband signal, that is, its frequency is restricted to a very narrow range.
		Narrowband interference is not the only kind of RFI (Radio Frequency Interference) that you will see in your graphs.
		To cover a broad range of frequencies with the necessary power would be unneccessarily wasteful of their energy resources.
	seticlassic.ssl.berkeley.edu /rfi/index.html (655 words)

	Interference: Defining the Source
		Interference is any unwanted radio frequency signal that prevents you from watching television, listening to your radio or stereo, or talking on your cordless telephone.
		Interference may prevent reception altogether, may cause only a temporary loss of a signal, or may affect the quality of the sound or picture produced by your equipment.
		A simple method of determining the location of electrical interference is by using a portable AM radio tuned to a quiet frequency at the lower end of the dial.
	www.fcc.gov /cgb/consumerfacts/interference.html (841 words)

	Radio Frequency Interference
		Radio frequency (RF) is an electromagnetic wave that oscillates between the audio and infrared in the electromagnetic spectrum.
		The interference is broadcast through the air as radio waves or conducted through power lines.
		If the radio shows that the RFI increases in your or your client’s business, determine if the interference is constant; it could be the lighting system or other electrical equipment causing the problem.
	www.signindustry.com /neon/articles/2004-02-16-RadioFrequency-RC-.php3 (1128 words)

	Radio Frequency Interference - Definition of Radio Frequency Interference by Webster's Online Dictionary (Site not responding. Last check: 2007-10-30)
		Radio Frequency Interference - (RFI) Electromagnetic radiation which is emitted by electrical circuits carrying rapidly changing signals, as a by-product of their normal operation, and which causes unwanted signals (interference or noise) to be induced in other circuits.
		The efficiency of the radiation is dependant on the height above the ground or power plane (at RF one is as good as the other) and the length of the conductor in relationship to the wavelength of the signal component (fundamental, harmonic or transient (overshoot, undershoot or ringing)).
		At lower frequencies, such as 133 MHz, radiation is almost exclusively via I/O cables; RF noise gets onto the power planes and is coupled to the line drivers via the VCC and ground pins.
	www.webster-dictionary.org /definition/Radio%20Frequency%20Interference (381 words)

	Easy solutions to Radio Frequency Interference (Site not responding. Last check: 2007-10-30)
		Radio Frequency Interference (RFI) can be described as any unwanted radio frequency signal, which interferes with another, desired signal.
		The radio antenna system and receiver have been designed for reception of very weak signals, often as low as 2 or 3 micro volts (millionth of a volt).
		The first is to prevent the radio interference from reaching the antenna by shielding.
	www.dieselduck.ca /library/tech_notes/radio_interference.htm (2634 words)

	Hallman Fence Systems - Fencer school - Radio frequency interference (RFI)
		Radio frequency interference (RFI for short) is nearly always caused by the fence rather than the fence controller.
		RFI does not mean the faint click usually heard on most barn radios if there is an electric fence close by, but very loud radio or television clicks, often accompanied by disruption of a clear picture.
		With the radio turned on but tuned between two AM stations, walk along the fence.
	www.hallman.ca /radio.htm (392 words)

	RADIO FREQUENCY INTERFERENCE (Site not responding. Last check: 2007-10-30)
		The cosmic radio signals that astronomers try to detect from distant stars and galaxies are typically billions of times weaker than the radio station signals picked up by home radios in the AM and FM bands.
		The regulation of radio transmissions in both the public and private sectors is necessary in order to prevent users of the radio spectrum for interfering with each other.
		Because of the faintness of the cosmic radio signals and the great sensitivies of radio telescopes, radio astronomers are particularly dependent on federal regulations to preserve some segments of the radio spectrum free from man-made transmissions.
	astrosun.tn.cornell.edu /faculty/haynes/asat/rfi.html (326 words)

	RSM ~ Radio Frequency Interference (Site not responding. Last check: 2007-10-30)
		bands of radio spectrum under a self-management agreement, but will assist on a case by case basis when non compliance with Electromagnetic Compliance legislation is suspected or safety to life or property is involved.
		Interference is seldom continuous, thus it is important to keep records of when the interference occurs.
		A small number of people do experience interference from devices external to their home which can be resolved by themselves or with the help of a service technician.
	www.rsm.govt.nz /rfi/index.html (470 words)

	RFI Services - Radio Frequency Interference and Power Line Noise
		Radio Frequency Interference (RFI) is any unwanted signal, which prevents reception of the best possible signal from the source (Radio, TV station) you want to receive.
		Interference may prevent reception altogether, may cause a temporary loss of the desired signal, or may affect the quality of the sound or picture produced by your equipment.
		Interference to electronic equipment is a frustrating problem and many times an indication of a hazardous condition; fortunately, there is a solution.
	www.rfiservices.com (259 words)

	Radio frequency interference
		Radio frequency interference (RFI) is often overlooked as a problem factor.
		Interference can be caused by any source of radio transmissions near a computer system.
		Radio frequency interference is generally more of a problem when you are networking computers.
	online.nmit.vic.edu.au /police/hardware/2_3h.htm (212 words)

	Sheridan Media - Radio Frequency Interference
		Radio Frequency Interference (RFI) is the reception of a radio or TV signal on a device not normally expected to do so.
		The FCC authorizes each radio station's frequency and power, and stations are required to monitor and maintain strict technical standards of operation.
		If you still hear the radio on the phone on all of the jacks, the telephone you are using may be at fault.
	www.sheridanmedia.com /site/rfi.html (1085 words)

	Radio-Frequency Interference
		At 20 cm, interference is most serious to the D configuration, as the fringe rates in other configurations are often sufficient to reduce interference to tolerable levels.
		Observers can use Table 10 to assist in deciding which center frequencies and bandwidths are most likely to result in good data at L band.
		Interference is relatively infrequent in the evenings and on weekends, but during the day, very strong interference - sufficient to saturate the receivers - is common.
	www.vla.nrao.edu /astro/guides/vlas/current/node19.html (1316 words)

	RFI : Technical Reference: Radio Frequency Interference
		Using ferrites for interference suppression - This tutorial is meant to shed some light on the use of ferrites, and also presents some comparative frequency domain measurements both to illustrate some of the points, and to give designers an idea of what they might expect in using and specifying a ferrite component
		Interference Handbook - Interference to home electronic equipment is a frustrating problem; but, fortunately, there are several ways to deal with it.
		Ferrite on Reducing RFI - Using ferrite to reduce radio frequency interference with your PC monitor or antennas with your receivers or transceivers.
	www.dxzone.com /catalog/Technical_Reference/Radio_Frequency_Interference (1538 words)

	Interference from Radio Frequency Fields - FMS
		Depending on the type of equipment, radio frequency fields are normally considered to present a hazard to standard office electronic equipment when the field strength exceeds 1 to 3 V/m.
		Conducted interference may originate from the coupling of ambient radiated interference or may be capacitively, inductively or galvanically induced in the cable by an emitting source.
		At audio and lower radio frequencies, EMI is primarily caused by conduction.
	www.fms-corp.com /interferenceconcerns_rffields.php4 (506 words)

	An explanation of radio frequency interference (rfi) and electromagnetic interference (emi)
		Where displays are concerned, interference occurs by the transmission of an interfering signal in the form of an electromagnetic wave and, for the frequencies with which we are usually concerned, is termed radio frequency interference (rfi) or electromagnetic interference (emi).
		Upon meeting such a shield, the signal will be partly reflected at the surface due to the resistive part of the impedance mis-match (conductivity of the shield) and that which continues through will be reduced by the reactive part of the shield impedance (the magnetic permeability of the material).
		This primarily specifies the acceptable disturbance levels for apparatus used in a domestic environment where the use of TV and radio broadcast receivers may be expected within a distance of 10 metres from the display.
	www.opticalfilters.co.uk /ws/technicalinformation.html (595 words)

	radio frequency radio frequency ablation radio frequency identification police radio frequency radio scanner frequency ...
		However, Wireless integrated has recently taken the strategic decision to concentrate largely on the unique radio technology that the company has developed over the past few years.
		Whilst most third party radio modules and radio ASIC technology can be used with our hardware it is the Wireless Integrated software that provides the key to our radio solutions.
		These blocks have a variety of uses from low noise low dropout applications for radio to battery charging and current monitoring applications.
	www.wirelessintegrated.com /wireless_technology_company_india.htm (1030 words)

	introduction
		Increasing congestion of the radio spectrum is making astrophysical research in the designated radio and microwave bands ever more difficult, and the situation is quite a bit worse outside the bands protected for astronomy.
		Every year, an increasing amount of radio frequency spectrum in the VHF, UHF, and microwave bands is being used to support new commercial and military ventures, and all have the potential to interfere with radio astronomy observations.
		Adaptive interference cancellation is a real-time approach to interference excision that has not been used before in radio astronomy.
	www.valdosta.edu /~cbarnbau/WebHelpRFI/introduction.htm (844 words)

	FAQ RFI control, radio frequency noise suppression, modem protectors, voltage regulators, power conditioners, surge ...
		Radio stations, cellular phones, Citizen's Band and police radio, welding equipment, small office or household appliances, fluorescent lights, loose electrical connections, defective AC Power plugs, cords or sockets are among the many sources of electrical interference.
		Interference may cause erratic program operation; or it might cause errors in data processing (we've all heard the old anecdote of a $1,000,000 check being issued for a $1 refund).
		Since Radio Frequency Interference may emanate from many portions of the offending device, shielding efforts may be required in severe situations.
	www.elect-spec.com /faqrfi.htm (1021 words)

	Radio Frequency Interference
		One of the frequent sources of error in breath alcohol testing is from Radio Frequency Interference, or RFI.
		On one side of the cell phone debate is Nextel Communications, whose frequencies are interspersed among those belonging to public safety.
		Nextel was assigned the frequencies by the Federal Communications Commission prior to the cell phone boom, when it was thought.
	www.1800duilaws.com /article/rfi.asp (813 words)

	Garage door remote frequency interference
		Our intent is to inform you of a radio frequency problem that is currently affecting two specific locations of the country, as well as give you information regarding our suggested resolution so that you can resolve this problem, in the event that your garage door opener is affected.
		A new Land Mobile Radio (LMR) communication system, operating on 380 MHz to 400MHz, is causing interference with garage door openers, resulting in poor transmitter range around Eglin Air Force Base in Florida and a Navy Depot in Mechanicsburg, Pennsylvania, where systems are currently being tested and used.
		The system uses handheld radios communicating with local repeaters and it is our understanding that it will be implemented across the nation, with a recommended final rollout of January 2008.
	www.garage-doors-and-parts.com /remote-interference.html (411 words)

	UC Berkeley Radio Frequency Interference
		Users of telecommunications radio frequency transmitters and receivers shall operate such equipment in compliance with regulations of the Federal Communications Commission.
		In particular, users shall not interfere with other station operators or other users on the same station, regardless of whether such operators or users are affiliated with the University.
		This includes monitoring the transmitting frequency for communications in progress and such other measures as may be necessary to minimize the potential for causing interference.
	radio.cns.berkeley.edu /rfi.shtml (626 words)

	Telephone Interference Instant Overview
		Telephone RFI (Radio Frequency Interference) takes place when equipment connected to a telephone circuit detects RF energy and acts like a radio receiver.
		Interference may also corrupt fax/modem data transfer and/or disrupt proper operation of equipment controls and operating features.
		Another excellent reference is Radio Frequency INTERFERENCE: How to Find It and Fix It published by the American Radio Relay League.
	www.k-comfilters.com /inst_ov.asp (296 words)

	COMAR Mobile Phone TIS
		This report addresses the concerns that have been expressed by some members of the public about the safety of exposure to radio frequency (RF) radiation from handheld communications devices, with particular reference to cellular telephone handsets.
		A potential exists for interference between hand-held units and some medical devices that may be located in close proximity to them (within a few centimeters).
		Sometimes, a distinction is drawn between radio waves, which have frequencies between 3 kHz and 1 GHz, and microwaves, which have a frequency between 1 GHz and 300 GHz.
	ewh.ieee.org /soc/embs/comar/phone.htm (3314 words)

	Cellular Phone Interference and 800 MHz Public Safety Radio Systems: An Unforeseen and Dangerous Problem
		The interference problem stems from the fact that the Federal Communications Commission failed to anticipate in the 1980s the rise of the cellular telephone industry, and assigned the newest public safety frequencies to a band adjacent to the cellular frequencies.
		When a public safety radio user is far away from the centrally-located base station, and is near a cellular site, the cellular site may overwhelm the public safety radio.
		Nextel, commonly cited as one of the principal agents behind the interference recognizes that there is a problem with cellular and other commercial radio service in the 800 MHz band and is working actively with some communities to resolve the interference issues.
	www.davidschoenberger.net /cellularinterference (810 words)

	Radio frequency interference mitigation for detection of extended sources with an interferometer
		Radio frequency interference mitigation for detection of extended sources with an interferometer
		Radio frequency interference (RFI) is a significant problem for current and future radio telescopes.
		Citation: Bower, G. Radio frequency interference mitigation for detection of extended sources with an interferometer, Radio Sci.
	www.agu.org /pubs/crossref/2005/2004RS003141.shtml (283 words)

	8 RFI (Radio Frequency Interference)
		At radio frequencies there are a few narrow radio astronomy bands that are exclusively reserved for doing radio astronomy.
		It means that radio emissions in these bands are forbidden and RFI should not occur.
		In order to minimize the effect of interference, standard frequency range are available for continuum observations (see § 5).
	www.astron.nl /wsrt/wsrtGuide/node9.html (287 words)

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