beat

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

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

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.

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.

beat

[bēt]

(physics)

The periodic variation in amplitude of a wave that is the superposition of two simple harmonic waves of different frequencies.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

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.

An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved