beat

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beat

1. Physics the low regular frequency produced by combining two sounds or electrical signals that have similar frequencies
2. Prosody the accent, stress, or ictus in a metrical foot
3. Nautical a course that steers a sailing vessel as close as possible to the direction from which the wind is blowing
4. 
a. the act of scouring for game by beating
b. the organized scouring of a particular woodland so as to rouse the game in it
c. the woodland where game is so roused
5. Fencing a sharp tap with one's blade on an opponent's blade to deflect it

Beat

A variation in the intensity of a composite wave which is formed from two distinct waves with different frequencies. Beats were first observed in sound waves, such as those produced by two tuning forks with different frequencies. Beats also can be produced by other waves. They can occur in the motion of two pendulums of different lengths and have been observed among the different-frequency phonons in a crystal lattice.

One important application of beat phenomena is to use one object with an accurately known frequency to determine the unknown frequency of another such object. The beat-frequency or heterodyne oscillator also operates by producing beats from two frequencies.

beat

[bēt]
(physics)
The periodic variation in amplitude of a wave that is the superposition of two simple harmonic waves of different frequencies.

beat

i. A low-frequency vibration produced when two sources of vibration act on the same object at the same time. For example, in a multiengine airplane, if two engines have slightly different RPM, airframe vibrations produced by these engines will produce a very noticeable beat.
ii. When two waves are combined or superimposed, a beat occurs if two frequencies are not the same. Waves beat together to create the appearance of either a change in amplitude, if the frequencies differ by a few hertz (Hz), or new frequencies, called beat frequencies or heterodynes, if the original frequencies are far apart.
References in periodicals archive ?
Extra beat bobbies started patrolling last week and community street wardens have gone into action to help stamp out trouble and vandalism.
Extra beat bobbies are being drafted in to patrol the streets and, with the help of the town's CCTV cameras, will be providing a strong presence during the evening.
THE Home Office is considering its next move after being presented with a 3,000-name petition calling for extra beat bobbies.
People are asked to consider a dozen issues - including extra beat bobbies, anti-social behaviour, speeding traffic, drugs and alcohol and Neigh-bourhood Watch - and score them in order of importance.
Officers made 52 arrests in the run-up to the festive period after deploying extra beat bobbies to the town centre streets as part of Operation Aldridge.
Up to 30 extra beat bobbies and plain clothes officers flooded the town centre and suburbs in the first stage of Operation Tranquillity yesterday afternoon.
EXTRA beat bobbies and plain clothes officers took to the streets of Leamington today for a high-profile police crackdown on burglars, drug dealers and petty thieves.
An occasional irregularity in pulse, such as a missed beat or extra beats, is common and nothing to worry about.
Nonetheless, the American College of Cardiology/American Heart Association guidelines on the management of PVCs state that if a patients history is consistent with premature extra beats, potential exacerbating factors such as caffeine, alcohol and nicotine should be eliminated.
They struggle decoding RI carols they've already heard, presumably because their bodies sense that all those extra beats are superfluous.
At once angular and fluid, she moved with incomprehensible speed and lightness; her pas battus (steps made with extra beats of the foot) and the tiny twist of her fingers as she extended her arms were as delicate and organic as the flick of a cat's whiskers.