interference

in·ter·fer·ence

I0186100 (ĭn′tər-fîr′əns)n.1. a. The act or an instance of hindering, obstructing, or impeding.b. Something that hinders, obstructs, or impedes.2. a. Sports Illegal obstruction or hindrance of an opposing player, such as hindrance of a receiver by a defender in football, hindrance of a fielder by a base runner in baseball, or checking a player not in possession of the puck in ice hockey.b. Football The legal blocking of defensive tacklers to protect and make way for the ball carrier.3. Physics The variation of wave amplitude that occurs from the superposition of two or more waves.4. Electronics a. The inhibition or prevention of clear reception of broadcast signals.b. The distorted portion of a received signal.5. The negative or distorting effect that new learning can have on previous learning or that previous learning can have on new learning.

in′ter·fer·en′tial (-fə-rĕn′shəl) adj.

interference

(ˌɪntəˈfɪərəns) n1. the act or an instance of interfering2. (General Physics) physics the process in which two or more coherent waves combine to form a resultant wave in which the displacement at any point is the vector sum of the displacements of the individual waves. If the individual waves converge the resultant is a system of fringes. Two waves of equal or nearly equal intensity moving in opposite directions combine to form a standing wave3. (Telecommunications) Also called: radio interference any undesired signal that tends to interfere with the reception of radio waves4. (Aeronautics) aeronautics the effect on the flow pattern around a body of objects in the vicinity interferential adj

in•ter•fer•ence

(ˌɪn tərˈfɪər əns)

n. 1. an act, fact, or instance of interfering. 2. something that interferes. 3. the process in which waves, as of light or sound, of the same frequency combine to reinforce or cancel each other, the amplitude of the resulting wave being equal to the sum of the amplitudes of the combining waves. 4. a. a jumbling of radio signals, caused by the reception of undesired ones. b. the signals or device producing the incoherence. 5. Football. a. the act of a teammate or of teammates legally running ahead of a ballcarrier and blocking prospective tacklers: to run interference for the halfback. b. such a teammate or such teammates collectively. c. the act of illegally hindering an opponent from catching a forward pass or a kick. 6. the distorting or inhibiting effect of previously learned behavior on subsequent learning. [1775–85] in`ter•fe•ren′tial (-fəˈrɛn ʃəl) adj.

in·ter·fer·ence

(ĭn′tər-fîr′əns)1. The wave that forms when two or more waves of the same or different frequencies come together. The amplitude of the resulting wave will be either larger or smaller than the amplitude of the individual waves, depending on whether or not their peaks and troughs match up. ♦ If the peaks of the waves match up, the amplitude of the resulting wave will be larger than that of the individual waves. This is called constructive interference. ♦ If the peaks and troughs of the individual waves do not match up, the resulting amplitude is smaller. This interference is called destructive interference. See more at wave.2. In electronics, the distortion or interruption of one broadcast signal by others.

interference

1. The effects of imposing one set of waves on another.2. This occurs when the pass receiver or pass defender is tackled, blocked or pushed while the ball is still in the air.3. A minor penalty is imposed if a player interferes with or impedes the progress of an opponent not in possession of the puck.

Thesaurus

Noun	1.	interference - a policy of intervening in the affairs of other countriesinterventionforeign policy - a policy governing international relationsnoninterference, nonintervention - a foreign policy of staying out of other countries' disputes
	2.	interference - the act of hindering or obstructing or impedinghinderance, hindrancehuman action, human activity, act, deed - something that people do or cause to happenfoiling, thwarting, frustration - an act of hindering someone's plans or effortsantagonism - (biochemistry) interference in or inhibition of the physiological action of a chemical substance by another having a similar structureobstruction - the act of obstructing; "obstruction of justice"complication - the act or process of complicatingdeterrence - the act or process of discouraging actions or preventing occurrences by instilling fear or doubt or anxietyprevention, bar - the act of preventing; "there was no bar against leaving"; "money was allocated to study the cause and prevention of influenza"
	3.	interference - electrical or acoustic activity that can disturb communicationnoise, disturbanceclutter - unwanted echoes that interfere with the observation of signals on a radar screentrouble - an event causing distress or pain; "what is the trouble?"; "heart trouble"background signal, background - extraneous signals that can be confused with the phenomenon to be observed or measured; "they got a bad connection and could hardly hear one another over the background signals"crosstalk, XT - the presence of an unwanted signal via an accidental couplingfadeout - a gradual temporary loss of a transmitted signal due to electrical disturbancesjitter - small rapid variations in a waveform resulting from fluctuations in the voltage supply or mechanical vibrations or other sourcesatmospheric static, atmospherics, static - a crackling or hissing noise caused by electrical interferencewhite noise - a noise produced by a stimulus containing all of the audible frequencies of vibration; "white noise is a good masking agent"
	4.	interference - (American football) blocking a player's path with your body; "he ran interference for the quarterback"American football, American football game - a game played by two teams of 11 players on a rectangular field 100 yards long; teams try to get possession of the ball and advance it across the opponents goal line in a series of (running or passing) playsblocking, block - the act of obstructing or deflecting someone's movements
	5.	interference - any obstruction that impedes or is burdensomehinderance, hindrance, preventative, preventive, encumbrance, incumbrance, hitchclog - any object that acts as a hindrance or obstructionimpedimenta, obstruction, obstructor, obstructer, impediment - any structure that makes progress difficultspeed bump - a hindrance to speeding created by a crosswise ridge in the surface of a roadway

interference

noun1. intrusion, intervention, meddling, opposition, conflict, obstruction, prying, impedance, meddlesomeness, intermeddling They can now set up cheap fares without interference from the government.2. static, feedback, disturbance, disruption, fuzz Users complained of interference and background noise.

interference

nounThe act or an instance of interfering or intruding:intervention, intrusion, meddling, obtrusion.

Translations

干扰干涉

interfere

(intəˈfiə) verb1. (often with in, ~with) to (try to) become involved in etc, when one's help etc is not wanted. I wish you would stop interfering (with my plans); Don't interfere in other people's business!干预2. (with with) to prevent, stop or slow down the progress of. He doesn't let anything interfere with his game of golf on Saturday mornings.妨碍ˌinterˈference noun1. the act of interfering. She was infuriated by his mother's interference in their holiday arrangements.干涉2. (the spoiling of radio or television reception by) the noise caused by programmes from another station, bad weather etc. This television set picks up a lot of interference.干扰ˌinterˈfering adjectivean interfering old woman.多管闲事的

interference

interference,

in physics, the effect produced by the combination or superposition of two systems of waveswave,
in physics, the transfer of energy by the regular vibration, or oscillatory motion, either of some material medium or by the variation in magnitude of the field vectors of an electromagnetic field (see electromagnetic radiation).
..... Click the link for more information. , in which these waves reinforce, neutralize, or in other ways interfere with each other. Interference is observed in both sound waves and electromagnetic waves, especially those of visible light and radio.

Interference in Sound Waves

When two soundsound,
any disturbance that travels through an elastic medium such as air, ground, or water to be heard by the human ear. When a body vibrates, or moves back and forth (see vibration), the oscillation causes a periodic disturbance of the surrounding air or other medium that
..... Click the link for more information. waves occur at the same time and are in the same phase, i.e., when the condensations of the two coincide and hence their rarefactions also, the waves reinforce each other and the sound becomes louder. This is known as constructive interference. On the other hand, two sound waves occurring simultaneously and having the same intensity neutralize each other if the rarefactions of the one coincide with the condensations of the other, i.e., if they are of opposite phase. This canceling is known as destructive interference. In this case, the result is silence.

Alternate reinforcement and neutralization (or weakening) take place when two sound waves differing slightly in frequency are superimposed. The audible result is a series of pulsations or, as these pulsations are called commonly, beats, caused by the alternate coincidence of first a condensation of the one wave with a condensation of the other and then a condensation with a rarefaction. The beat frequency is equal to the difference between the frequencies of the interfering sound waves.

Interference in Light Waves

Lightlight,
visible electromagnetic radiation. Of the entire electromagnetic spectrum, the human eye is sensitive to only a tiny part, the part that is called light. The wavelengths of visible light range from about 350 or 400 nm to about 750 or 800 nm.
..... Click the link for more information. waves reinforce or neutralize each other in very much the same way as sound waves. If, for example, two light waves each of one color (monochromatic waves), of the same amplitude, and of the same frequency are combined, the interference they exhibit is characterized by so-called fringes—a series of light bands (resulting from reinforcement) alternating with dark bands (caused by neutralization). Such a pattern is formed either by light passing through two narrow slits and being diffracted (see diffractiondiffraction,
bending of waves around the edge of an obstacle. When light strikes an opaque body, for instance, a shadow forms on the side of the body that is shielded from the light source.
..... Click the link for more information. ), or by light passing through a single slit. In the case of two slits, each slit acts as a light source, producing two sets of waves that may combine or cancel depending upon their phase relationship. In the case of a single slit, each point within the slit acts as a light source. In all cases, for light waves to demonstrate such behavior, they must emanate from the same source; light from distinct sources has too many random differences to permit interference patterns.

The relative positions of light and dark lines depend upon the wavelength of the light, among other factors. Thus, if white light, which is made up of all colors, is used instead of monochromatic light, bands of color are formed because each color, or wavelength, is reinforced at a different position. This fact is utilized in the diffraction grating, which forms a spectrumspectrum,
arrangement or display of light or other form of radiation separated according to wavelength, frequency, energy, or some other property. Beams of charged particles can be separated into a spectrum according to mass in a mass spectrometer (see mass spectrograph).
..... Click the link for more information. by diffraction and interference of a beam of light incident on it. Newton's rings also are the result of the interference of light. They are formed concentrically around the point of contact between a glass plate and a slightly convex lens set upon it or between two lenses pressed together; they consist of bright rings separated by dark ones when monochromatic light is used, or of alternate spectrum-colored and black rings when white light is used. Various natural phenomena are the result of interference, e.g., the colors appearing in soap bubbles and the iridescence of mother-of-pearl and other substances.

Interference as a Scientific Tool

The experiments of Thomas Young first illustrated interference and definitely pointed the way to a wave theory of light. A. J. Fresnel's experiments clearly demonstrated that the interference phenomena could be explained adequately only upon the basis of a wave theory. The thickness of a very thin film such as the soap-bubble wall can be measured by an instrument called the interferometer. When the wavelength of the light is known, the interferometer indicates the thickness of the film by the interference patterns it forms. The reverse process, i.e., the measurement of the length of an unknown light wave, can also be carried out by the interferometer.

The Michelson interferometer used in the Michelson-Morley experiment of 1887 to determine the velocity of light had a half-silvered mirror to split an incident beam of light into two parts at right angles to one another. The two halves of the beam were then reflected off mirrors and rejoined. Any difference in the speed of light along the paths could be detected by the interference pattern. The failure of the experiment to detect any such difference threw doubt on the existence of the etherether
or aether,
in physics and astronomy, a hypothetical medium for transmitting light and heat (radiation), filling all unoccupied space; it is also called luminiferous ether. In Newtonian physics all waves are propagated through a medium, e.g.
..... Click the link for more information. and thus paved the way for the special theory of relativityrelativity,
physical theory, introduced by Albert Einstein, that discards the concept of absolute motion and instead treats only relative motion between two systems or frames of reference.
..... Click the link for more information. .

Another type of interferometer devised by Michelson has been applied in measuring the diameters of certain stars. The radio interferometer consists of two or more radio telescopes separated by fairly large distances (necessary because radio waves are much longer than light waves) and is used to pinpoint and study various celestial sources of radiation in the radio range. Astronomical interferometers consisting of two or more optical telescopes are used to enhance visible images of distant celestial objects. See radio astronomyradio astronomy,
study of celestial bodies by means of the electromagnetic radio frequency waves they emit and absorb naturally. Radio Telescopes

Radio waves emanating from celestial bodies are received by specially constructed antennas, called radio telescopes,
..... Click the link for more information. ; virtual telescopevirtual telescope,
a computerized interferometer (see interference) that merges the images from two or more telescopes to obtain a single, large, enhanced image. The image in each telescope is made from electromagnetic waves (light waves from an optical telescope, radio waves
..... Click the link for more information. .

interference

1. Unwanted signals picked up by a radio telescope or other electronic equipment; the signals usually arise from terrestrial sources but occasionally come from the Sun or Jupiter. 2. The interaction of two sets of waves to produce patterns of high and low intensity (interference fringes). For this to happen the two beams of light or other radiation must be coherent, i.e. they must be related with respect to phase and have the same, or nearly the same, wavelength. They must intersect at a fairly small angle and not differ too much in intensity. In addition, they must not be polarized in mutually perpendicular planes.

The interference pattern of fringes formed at a particular position is the sum of the intensities of the two interacting waves at that position. The fringes occur because of differences in pathlength between interacting waves, i.e. because of unequal distances from source to interaction point. If the difference is a whole number of wavelengths, then wave peaks (or troughs) of the two interacting waves coincide and the waves reinforce one another, producing a bright fringe when light waves are involved; this is termed constructive interference. If the path difference is an integral number of half wavelengths a peak coincides with a wave trough and a dark fringe results; this is destructive interference.

Both constructive and destructive interference of light can be produced by means of thin films of uniform thickness, as used in interference filters. Waves of selected wavelengths are reflected from the front and back surfaces of the film and by a suitable choice of film composition and thickness the waves will either be reinforced or will cancel each other.

Interference

(1) In biology, the influence of the crossover of homologous chromosomes in one area on the appearance of new crossovers in neighboring areas. Most often this type of interference inhibits the appearance of a new crossover in a neighboring area; hence, in experiments the percentage of double-crossover individuals as a rule turns out to be lower than that theoretically expected. Double crossover is particularly strongly suppressed by interference when there are small distances between the genes.

(2) In medicine, interference of viruses is the suppression by one virus of the effect of another when there is a mixed infection.In such cases the first virus is called the interfering one, and the second is called the pretender.

Interference

(of waves), superposition of two or more waves in space, producing an increase or decrease in the amplitude of the resulting wave. Interference is characteristic of all waves, regardless of their nature: waves on the surface of a liquid, elastic waves (such as sound waves), and electromagnetic waves (such as radio or light waves).

If two waves are propagating through space, then the resulting oscillation at every point is the geometric sum of the oscillations corresponding to each of the component waves. This “superposition principle” is usually strictly obeyed and is violated only in the propagation of waves in a medium if the amplitude (intensity) of the waves is very large. Wave interference is possible if the waves are coherent.

The simplest case of interference is the addition of two waves of identical frequency and phase. In this case, if the oscillations take place according to a sine (harmonic) law, the amplitude of the resultant wave at any point in space is

where A₁ and A₂ are the amplitudes of the component waves and ϕ is the phase difference between the waves at the point in question. If the waves are coherent, the phase difference ϕ remains unchanged at the given point but may change from point to point, leading to a distribution of the amplitudes of the resultant waves with alternating maximums and minimums. If the amplitudes of the component waves are the same (that is, if A₁A₂), the maximum amplitude is equal to twice the amplitude of each wave, and the minimum amplitude is equal to zero. The geometric loci of equal phase difference, which specifically corresponds to the maximums or minimums, are surfaces that depend on the properties and location of the sources emitting the component waves. In the case of two point sources emitting spherical waves, the surfaces are hyperboloids of rotation.

Another important instance of interference is the superposition of two plane waves propagating in opposite directions (for example, incident and reflected waves). In this case standing waves are produced.

The average values of the energy flux of the wave over the period is proportional to the square of the amplitude. Therefore, it follows from the equation for the resultant amplitude that interference involves a redistribution of the energy flux of the wave in space. The distribution of amplitudes with alternating minimums and maximums, which is characteristic of interference, remains stationary in space or moves so slowly that the maximums and minimums are not displaced by a quantity comparable to the distance between them during the time required for the observation, and it may be observed only when the waves are coherent. If the waves are incoherent, then the phase difference ϕ changes rapidly and at random, assuming all possible values, so that the average value of cos ϕ is zero. In this case, the average value of the amplitude of the resultant wave is found to be the same at different points, the maximums and minimums are blurred, and the interference pattern disappears. In this case, the mean square of the resultant amplitude is equal to the sum of the mean squares of the amplitudes of the component waves—that is, superposition of waves involves the addition of the energy fluxes or intensities.

The main features of the interference phenomenon described above apply equally to elastic and electromagnetic waves. However, although coherence of sonic and radio waves is easily achieved (for example, by using the same current to feed various antennas or speakers), before the development of the laser coherent light beams could be produced only by the same light source, using special methods. Another essential difference between the methods of interference production involving sonic and radio waves on the one hand and light waves on the other is related to the size of the emitters. The size of the sonic and radio-wave emitters is almost always comparable with the length of the emitted wave, whereas in the case of light waves, the size of the source is almost always large in comparison with the wavelength. For this reason, the problem of the extent of the source plays a significant role in the interference of light waves. Because of these special features, light interference may be observed only under special conditions.

Wave interference is of great importance in both research and technology. Since a definite relationship exists among the wavelength, the path difference of interfering rays, and the position of maximums and minimums, knowledge of the path difference of the interfering waves makes possible determination of the wavelength from the positions of the minimums and maximums and, conversely, knowledge of the wavelength makes possible determination of the path difference of the rays (that is, measurement of distances) from the positions of the maximums and minimums. Instruments using wave interference include optical interferometers, radio interferometers, and interferential radio range finders.

REFERENCES

Elementarnyi uchebnik fiziki, 6th ed., vol. 3, ch. 3. Edited by G. S. Landsberg. Moscow, 1970.
Gorelik, G. S. Kolebaniia i volny, 2nd ed. Moscow-Leningrad, 1959.
Landsberg, G. S. Optika, 4th ed. Moscow, 1957. (Obshchii kurs fiziki, vol. 3.)

interference

[‚in·tər′fir·əns] (analytical chemistry) A systematic error in measurement that occurs when concomitants are present in the sample being analyzed. (communications) Any undesired energy that tends to interfere with the reception of desired signals. Also known as electrical interference; radio interference. (physics) The variation with distance or time of the amplitude of a wave which results from the superposition (algebraic or vector addition) of two or more waves having the same, or nearly the same, frequency. Also known as wave interference.

interference

The destruction or distortion of one wave by another, or one broadcast by another. Any interference adversely affects the quality of a received signal or message.

interference

1. Physics the process in which two or more coherent waves combine to form a resultant wave in which the displacement at any point is the vector sum of the displacements of the individual waves. If the individual waves converge the resultant is a system of fringes. Two waves of equal or nearly equal intensity moving in opposite directions combine to form a standing wave 2. Aeronautics the effect on the flow pattern around a body of objects in the vicinity

interference

in·ter·fer·ence

interference

in•ter•fer•ence

in·ter·fer·ence

interference

interference

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interfere

interference

interference,

Interference in Sound Waves

Interference in Light Waves

Interference as a Scientific Tool

interference

Interference

Interference

REFERENCES

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in·ter·fer·ence

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Patient discussion about interference

Interference

Interference

interference

Synonyms for interference

noun intrusion

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noun static

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Synonyms for interference

noun the act or an instance of interfering or intruding

Synonyms

Synonyms for interference

noun a policy of intervening in the affairs of other countries

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Antonyms

noun the act of hindering or obstructing or impeding

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noun electrical or acoustic activity that can disturb communication

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noun (American football) blocking a player's path with your body

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noun any obstruction that impedes or is burdensome

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