HOME  TheInfoList.com 
Heaviside Condition The Heaviside condition, named for Oliver Heaviside Oliver Heaviside (1850–1925), is the condition an electrical transmission line must meet in order for there to be no distortion of a transmitted signal. Also known as the distortionless condition, it can be used to improve the performance of a transmission line by adding loading to the cable.Contents1 The condition 2 Background 3 Derivation3.1 Line characteristics 3.2 Characteristic impedance4 Practical use 5 See also 6 References 7 BibliographyThe condition[edit]Heaviside's model of a transmission line.A transmission line can be represented as a distributed element model of its primary line constants as shown in the figure. The primary constants are the electrical properties of the cable per unit length and are: capacitance C (in farads per meter), inductance L (in henries per meter), series resistance R (in ohms per meter), and shunt conductance G (in siemens per meter) [...More...]  "Heaviside Condition" on: Wikipedia Yahoo 

Radiotelephone A radiotelephone (or radiophone) is a communications system for transmission of speech over radio. Radiotelephone systems are very rarely interconnected with the public "land line" (POTS/PSTN) telephone network, and in some radio services, including GMRS,[1] such interconnection is prohibited. "Radiotelephony" means transmission of sound (audio) by radio, in contrast to radiotelegraphy (transmission of telegraph signals) or video transmission [...More...]  "Radiotelephone" on: Wikipedia Yahoo 

Telegrapher's Equations The telegrapher's equations (or just telegraph equations) are a pair of coupled, linear differential equations that describe the voltage and current on an electrical transmission line with distance and time. The equations come from Oliver Heaviside Oliver Heaviside who in the 1880s developed the transmission line model, which is described in this article. The model demonstrates that the electromagnetic waves can be reflected on the wire, and that wave patterns can appear along the line [...More...]  "Telegrapher's Equations" on: Wikipedia Yahoo 

Characteristic Impedance The characteristic impedance or surge impedance (usually written Z0) of a uniform transmission line is the ratio of the amplitudes of voltage and current of a single wave propagating along the line; that is, a wave travelling in one direction in the absence of reflections in the other direction. Characteristic impedance Characteristic impedance is determined by the geometry and materials of the transmission line and, for a uniform line, is not dependent on its length. The SI unit of characteristic impedance is the ohm. The characteristic impedance of a lossless transmission line is purely real, with no reactive component. Energy supplied by a source at one end of such a line is transmitted through the line without being dissipated in the line itself [...More...]  "Characteristic Impedance" on: Wikipedia Yahoo 

Impedance Matching In electronics, impedance matching is the practice of designing the input impedance of an electrical load or the output impedance of its corresponding signal source to maximize the power transfer or minimize signal reflection from the load. In the case of a complex source impedance ZS and load impedance ZL, maximum power transfer is obtained when Z S = Z L ∗ displaystyle Z_ mathrm S =Z_ mathrm L ^ * , where the asterisk indicates the complex conjugate of the variable. Where ZS represents the characteristic impedance of a transmission line, minimum reflection is obtained when Z S = Z L displaystyle Z_ mathrm S =Z_ mathrm L , The concept of impedance matching found first applications in electrical engineering, but is relevant in other applications [...More...]  "Impedance Matching" on: Wikipedia Yahoo 

Electrical Element Electrical elements are conceptual abstractions representing idealized electrical components, such as resistors, capacitors, and inductors, used in the analysis of electrical networks. All electrical networks can be analyzed as multiple electrical elements interconnected by wires. Where the elements roughly correspond to real components the representation can be in the form of a schematic diagram or circuit diagram. This is called a lumped element circuit model. In other cases infinitesimal elements are used to model the network in a distributed element model. These ideal electrical elements represent real, physical electrical or electronic components but they do not exist physically and they are assumed to have ideal properties, while actual electrical components have less than ideal properties, a degree of uncertainty in their values and some degree of nonlinearity [...More...]  "Electrical Element" on: Wikipedia Yahoo 

Rational Function In mathematics, a rational function is any function which can be defined by a rational fraction, i.e. an algebraic fraction such that both the numerator and the denominator are polynomials. The coefficients of the polynomials need not be rational numbers; they may be taken in any field K. In this case, one speaks of a rational function and a rational fraction over K. The values of the variables may be taken in any field L containing K [...More...]  "Rational Function" on: Wikipedia Yahoo 

Permeability (electromagnetism) In electromagnetism, permeability is the measure of the ability of a material to support the formation of a magnetic field within itself. Hence, it is the degree of magnetization that a material obtains in response to an applied magnetic field. Magnetic permeability Magnetic permeability is typically represented by the (italicized) Greek letter µ. The term was coined in September 1885 by Oliver Heaviside. The reciprocal of magnetic permeability is magnetic reluctance. In SI units, permeability is measured in henries per meter (H/m or H·m−1), or equivalently in newtons per ampere squared (N·A−2). The permeability constant (µ0), also known as the magnetic constant or the permeability of free space, is a measure of the amount of resistance encountered when forming a magnetic field in a classical vacuum [...More...]  "Permeability (electromagnetism)" on: Wikipedia Yahoo 

Cutoff Frequency In physics and electrical engineering, a cutoff frequency, corner frequency, or break frequency is a boundary in a system's frequency response at which energy flowing through the system begins to be reduced (attenuated or reflected) rather than passing through. Typically in electronic systems such as filters and communication channels, cutoff frequency applies to an edge in a lowpass, highpass, bandpass, or bandstop characteristic – a frequency characterizing a boundary between a passband and a stopband. It is sometimes taken to be the point in the filter response where a transition band and passband meet, for example, as defined by a halfpower point (a frequency for which the output of the circuit is −3 dB of the nominal passband value) [...More...]  "Cutoff Frequency" on: Wikipedia Yahoo 

Maxwell's Equations Maxwell's equations Maxwell's equations are a set of partial differential equations that, together with the Lorentz force Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits. The equations provide a conceptual underpinning for all electric, optical and radio technologies, including power generation, electric motors, wireless communication, cameras, televisions, computers etc. Maxwell's equations describe how electric and magnetic fields are generated by charges, currents, and changes of each other. One important consequence of the equations is that they demonstrate how fluctuating electric and magnetic fields propagate at the speed of light. Known as electromagnetic radiation, these waves may occur at various wavelengths to produce a spectrum from radio waves to γrays [...More...]  "Maxwell's Equations" on: Wikipedia Yahoo 

International Standard Book Number "ISBN" redirects here. For other uses, see ISBN (other).International Standard Book Book NumberA 13digit ISBN, 9783161484100, as represented by an EAN13 bar codeAcronym ISBNIntroduced 1970; 48 years ago (1970)Managing organisation International ISBN AgencyNo. of digits 13 (formerly 10)Check digit Weighted sumExample 9783161484100Website www.isbninternational.orgThe International Standard Book Book Number (ISBN) is a unique[a][b] numeric commercial book identifier. Publishers purchase ISBNs from an affiliate of the International ISBN Agency.[1] An ISBN is assigned to each edition and variation (except reprintings) of a book. For example, an ebook, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, and 10 digits long if assigned before 2007 [...More...]  "International Standard Book Number" on: Wikipedia Yahoo 

Neper The neper (symbol: Np) is a logarithmic unit for ratios of measurements of physical field and power quantities, such as gain and loss of electronic signals. The unit's name is derived from the name of John Napier, the inventor of logarithms. As is the case for the decibel and bel, the neper is a unit defined in the international standard ISO 80000. It is not part of the International System of Units (SI), but is accepted for use alongside the SI.[1]Contents1 Definition 2 Units 3 Applications 4 See also 5 Notes and references 6 Further reading 7 External linksDefinition[edit] Like the decibel, the neper is a unit in a logarithmic scale. While the bel uses the decadic (base10) logarithm to compute ratios, the neper uses the natural logarithm, based on Euler's number Euler's number (e ≈ 2.71828) [...More...]  "Neper" on: Wikipedia Yahoo 

Special Special Special or specials may refer to:Contents1 Music 2 Film and television 3 Other uses 4 See alsoMusic[edit] Special Special (album), a 1992 album by Vesta Williams "Special" (Garbage song), 1998 "Special [...More...]  "Special" on: Wikipedia Yahoo 

Telecommunication Telecommunication Telecommunication is the transmission of signs, signals, messages, words, writings, images and sounds or information of any nature by wire, radio, optical or other electromagnetic systems.[1][2] Telecommunication Telecommunication occurs when the exchange of information between communication participants includes the use of technology. It is transmitted either electrically over physiical media, such as cables, or via electromagnetic radiation.[3][4][5][6][7][8] Such transmission paths are often divided into communication channels which afford the advantages of multiplexing [...More...]  "Telecommunication" on: Wikipedia Yahoo 

History Of Telecommunication The history of telecommunication began with the use of smoke signals and drums in Africa, the Americas Americas and parts of Asia. In the 1790s, the first fixed semaphore systems emerged in Europe; however it was not until the 1830s that electrical telecommunication systems started to appear. This article details the history of telecommunication and the individuals who helped make telecommunication systems what they are today [...More...]  "History Of Telecommunication" on: Wikipedia Yahoo 