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Frequency Mixers
Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillation, oscillatory and vibration, vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. The interval of time between events is called the period. It is the Multiplicative inverse, reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times per minute (2 hertz), its period is one half of a second. Special definitions of frequency are used in certain contexts, such as the angular frequency in rotational or cyclical properties, when the rate of angular progress is measured. Spatial frequency is defined for properties that vary or cccur repeatedly in geometry or space. The unit of measurement of frequency in the International System of Units (SI) is the hertz, having the symbol Hz. Definitions and units For cyclical phenomena ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pendulum
A pendulum is a device made of a weight suspended from a pivot so that it can swing freely. When a pendulum is displaced sideways from its resting, equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. When released, the restoring force acting on the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth. The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum and also to a slight degree on the amplitude, the width of the pendulum's swing. Pendulums were widely used in early mechanical clocks for timekeeping. The regular motion of pendulums was used for timekeeping and was the world's most accurate timekeeping technology until the 1930s. The pendulum clock invented by Christiaan Huygens in 1656 became the world's standard timekeeper, used in homes and offices for 270 years, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Number Of Rotations
The turn (symbol tr or pla) is a unit of plane angle measurement that is the measure of a complete angle—the angle Subtended angle, subtended by a complete circle at its center. One turn is equal to radians, 360 degree (angle), degrees or 400 gradians. As an angular unit, one turn also corresponds to one cycle (symbol cyc or c) or to one revolution (symbol rev or r). Common related Frequency#Unit, units of frequency are ''cycles per second'' (cps) and ''revolutions per minute'' (rpm). The angular unit of the turn is useful in connection with, among other things, electromagnetic coils (e.g., transformers), rotating objects, and the winding number of curves. Divisions of a turn include the half-turn and quarter-turn, spanning a Angle#Individual angles, straight angle and a right angle, respectively; metric prefixes can also be used as in, e.g., centiturns (ctr), milliturns (mtr), etc. In the International System of Quantities, ISQ, an arbitrary "number of turns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotational Frequency
Rotational frequency, also known as rotational speed or rate of rotation (symbols ''ν'', lowercase Greek nu, and also ''n''), is the frequency of rotation of an object around an axis. Its SI unit is the reciprocal seconds (s−1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). Rotational frequency can be obtained dividing ''angular frequency'', ω, by a full turn (2 π radians): ''ν''ω/(2πrad). It can also be formulated as the instantaneous rate of change of the number of rotations, ''N'', with respect to time, ''t'': ''n''d''N''/d''t'' (as per International System of Quantities). (11 pages) Similar to ordinary period (physics), per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commutative Diagram Of Harmonic Wave Properties
In mathematics, a binary operation is commutative if changing the order of the operands does not change the result. It is a fundamental property of many binary operations, and many mathematical proofs depend on it. Perhaps most familiar as a property of arithmetic, e.g. or , the property can also be used in more advanced settings. The name is needed because there are operations, such as division (mathematics), division and subtraction, that do not have it (for example, ); such operations are ''not'' commutative, and so are referred to as noncommutative operations. The idea that simple operations, such as the multiplication (mathematics), multiplication and addition of numbers, are commutative was for many centuries implicitly assumed. Thus, this property was not named until the 19th century, when new algebraic structures started to be studied. Definition A binary operation * on a Set (mathematics), set ''S'' is ''commutative'' if x * y = y * x for all x,y \in S. An operat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean Surface Wave
In fluid dynamics, a wind wave, or wind-generated water wave, is a surface wave that occurs on the free surface of Body of water, bodies of water as a result of the wind blowing over the water's surface. The contact distance in the wind direction, direction of the wind is known as the ''Wind fetch, fetch''. Waves in the oceans can travel thousands of kilometers before reaching land. Wind waves on Earth range in size from small capillary wave, ripples to waves over high, being limited by wind speed, duration, fetch, and water depth. When directly generated and affected by local wind, a wind wave system is called a wind sea. Wind waves will travel in a great circle route after being generated – curving slightly left in the southern hemisphere and slightly right in the northern hemisphere. After moving out of the area of fetch and no longer being affected by the local wind, wind waves are called ''swell (ocean), swells'' and can travel thousands of kilometers. A noteworthy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotational Frequency
Rotational frequency, also known as rotational speed or rate of rotation (symbols ''ν'', lowercase Greek nu, and also ''n''), is the frequency of rotation of an object around an axis. Its SI unit is the reciprocal seconds (s−1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). Rotational frequency can be obtained dividing ''angular frequency'', ω, by a full turn (2 π radians): ''ν''ω/(2πrad). It can also be formulated as the instantaneous rate of change of the number of rotations, ''N'', with respect to time, ''t'': ''n''d''N''/d''t'' (as per International System of Quantities). (11 pages) Similar to ordinary period (physics), per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second
The second (symbol: s) is a unit of time derived from the division of the day first into 24 hours, then to 60 minutes, and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of Units (SI) is more precise: The second ..is defined by taking the fixed numerical value of the caesium frequency, Δ''ν''Cs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be when expressed in the unit Hz, which is equal to s−1. This current definition was adopted in 1967 when it became feasible to define the second based on fundamental properties of nature with caesium clocks. As the speed of Earth's rotation varies and is slowing ever so slightly, a leap second is added at irregular intervals to civil time to keep clocks in sync with Earth's rotation. The definition that is based on of a rotation of the earth is still used by the Universal Time 1 (UT1) system. Etymology "Minute" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycle Per Second
The cycle per second is a once-common English name for the unit of frequency now known as the ''hertz'' (Hz). Cycles per second may be denoted by c.p.s., c/s, or, ambiguously, just "cycles" (Cyc., Cy., C, or c). The term comes from repetitive phenomena such as sound waves having a frequency measurable as a number of oscillations, or cycles, per second. With the organization of the International System of Units in 1960, the cycle per second was officially replaced by the hertz, or reciprocal second, "s−1" or "1/s". Symbolically, "cycle per second" units are "cycle/second", while hertz is "Hz" or "s−1". For higher frequencies, ''kilocycles'' (kc), as an abbreviation of ''kilocycles per second'' were often used on components or devices. Other higher units like ''megacycle'' (Mc) and less commonly ''kilomegacycle'' (kMc) were used before 1960 and in some later documents. These have modern equivalents such as kilohertz (kHz), megahertz (MHz), and gigahertz (GHz). Following the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CGPM
The General Conference on Weights and Measures (abbreviated CGPM from the ) is the supreme authority of the International Bureau of Weights and Measures (BIPM), the intergovernmental organization established in 1875 under the terms of the Metre Convention through which member states act together on matters related to measurement science and measurement standards. The CGPM is made up of delegates of the governments of the member states and observers from the Associates of the CGPM. It elects the International Committee for Weights and Measures (abbreviated CIPM from the ) as the supervisory board of the BIPM to direct and supervise it. Initially the work of the BIPM concerned the kilogram and the metre, but in 1921 the scope of the Metre Convention was extended to accommodate all physical measurements and hence all aspects of the metric system. In 1960 the 11th CGPM approved the title International System of Units, usually known as "SI". The General Conference receives the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; ) is an international standards organization that prepares and publishes international standards for all electrical, electronics, electronic and related technologies. IEC standards cover a vast range of technologies from power generation, transmission and distribution to home appliances and office equipment, semiconductors, fibre optics, batteries, solar energy, nanotechnology, and marine energy, as well as many others. The IEC also manages four global conformity assessment systems that certify whether equipment, system or components conform to its international standards. All electrotechnologies are covered by IEC Standards, including energy production and distribution, electronics, magnetics and electromagnetics, electroacoustics, multimedia, telecommunications and medical technology, as well as associated general disciplines such as terminology and symbols, electromagnetic compatibility, measurement and performance, dependa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Hertz
Heinrich Rudolf Hertz (; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's equations of electromagnetism. Biography Heinrich Rudolf Hertz was born in 1857 in Hamburg, then a sovereign state of the German Confederation, into a prosperous and cultured Hanseatic family. His father was Gustav Ferdinand Hertz. His mother was Anna Elisabeth Pfefferkorn. While studying at the Gelehrtenschule des Johanneums in Hamburg, Hertz showed an aptitude for sciences as well as languages, learning Arabic. He studied sciences and engineering in the German cities of Dresden, Munich and Berlin, where he studied under Gustav R. Kirchhoff and Hermann von Helmholtz. In 1880, Hertz obtained his PhD from the University of Berlin, and for the next three years remained for post-doctoral study under Helmholtz, serving as his assistant. In 1883, Hertz took a post as a lecturer in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
