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Quarter Wave Impedance Transformer
A quarter-wave impedance transformer, often written as λ/4 impedance transformer, is a transmission line or waveguide used in electrical engineering of length one-quarter wavelength (λ), terminated with some known electrical impedance, impedance. It presents at its input the dual impedance, dual of the impedance with which it is terminated. The relationship between the characteristic impedance, ''Z''0, input impedance, ''Z''in and load impedance, ''Z''L is: \frac=\frac Alternatives to the quarter-wave impedance transformer include lumped circuits that can produce the impedance inverter function, and Stub (electronics), stubs for impedance matching. Applications At radio frequency, radio frequencies of upper VHF or higher up to microwave frequencies one quarter wavelength is conveniently short enough to incorporate the component within many products, but not so small that it cannot be manufactured using normal engineering tolerances, and it is at these frequencies where the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed-element Filter
A distributed-element filter is an electronic filter in which capacitance, inductance, and resistance (the elements of the circuit) are not localised in discrete capacitors, inductors, and resistors as they are in conventional filters. Its purpose is to allow a range of signal frequencies to pass, but to block others. Conventional filters are constructed from inductors and capacitors, and the circuits so built are described by the lumped element model, which considers each element to be "lumped together" at one place. That model is conceptually simple, but it becomes increasingly unreliable as the frequency of the signal increases, or equivalently as the wavelength decreases. The distributed-element model applies at all frequencies, and is used in transmission-line theory; many distributed-element components are made of short lengths of transmission line. In the distributed view of circuits, the elements are distributed along the length of conductors and are inextricably m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propagation Constant
The propagation constant of a sinusoidal electromagnetic wave is a measure of the change undergone by the amplitude and phase of the wave as it propagates in a given direction. The quantity being measured can be the voltage, the current in a circuit, or a field vector such as electric field strength or flux density. The propagation constant itself measures the dimensionless change in magnitude or phase per unit length. In the context of two-port networks and their cascades, propagation constant measures the change undergone by the source quantity as it propagates from one port to the next. The propagation constant's value is expressed logarithmically, almost universally to the base ''e'', rather than base 10 that is used in telecommunications in other situations. The quantity measured, such as voltage, is expressed as a sinusoidal phasor. The phase of the sinusoid varies with distance which results in the propagation constant being a complex number, the imaginary par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 wave travelling in one direction along the line in the absence of reflections in the other direction. Equivalently, it can be defined as the input impedance of a transmission line when its length is infinite. 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 (see below). Energy supplied by a source at one end of such a line is transmitted through the line without being dissipated in the line itself. A transmission line of finite length (lossless or lossy) that is terminated at one end with an impedance equal to the characteristic impedance appears to the sourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Line Animation Open Short2
Transmission or transmit may refer to: Science and technology * Power transmission ** Electric power transmission ** Transmission (mechanical device), technology that allows controlled application of power *** Automatic transmission *** Manual transmission * Signal transmission, the process of sending and propagating an analogue or digital information signal ** Analogue transmission, the process of sending and propagating an analogue signal ** Data transmission, the process of sending and propagating digital information ** Signaling (telecommunications), transmission of meta-information related to the actual transmission * Monetary transmission mechanism, process by which asset prices and general economic conditions are affected as a result of monetary policy decisions * Pathogen transmission, the passing of a disease from an infected host individual or group to a particular individual or group * Cellular signaling, transmission of signals within or between living cells * Heredity, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Admittance
In electrical engineering, admittance is a measure of how easily a circuit or device will allow a current to flow. It is defined as the multiplicative inverse, reciprocal of Electrical impedance, impedance, analogous to how Electrical resistance and conductance, conductance and resistance are defined. The SI unit of admittance is the siemens (unit), siemens (symbol S); the older, synonymous unit is mho, and its symbol is ℧ (an upside-down uppercase omega Ω). Oliver Heaviside coined the term ''admittance'' in December 1887. Heaviside used to represent the magnitude of admittance, but it quickly became the conventional symbol for admittance itself through the publications of Charles Proteus Steinmetz. Heaviside probably chose simply because it is next to in the alphabet, the conventional symbol for impedance. Admittance , measured in Siemens (unit), siemens, is defined as the inverse of Electrical impedance, impedance , measured in Ohm (unit), ohms: Y \equiv \frac electric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumped-element
The lumped-element model (also called lumped-parameter model, or lumped-component model) is a simplified representation of a physical system or circuit that assumes all components are concentrated at a single point and their behavior can be described by idealized mathematical models. The lumped-element model simplifies the system or circuit behavior description into a topology. It is useful in electrical systems (including electronics), mechanical multibody systems, heat transfer, acoustics, etc. This is in contrast to distributed parameter systems or models in which the behaviour is distributed spatially and cannot be considered as localized into discrete entities. The simplification reduces the State space (controls), state space of the system to a counting number, finite dimension, and the partial differential equations (PDEs) of the continuous (infinite-dimensional) time and space model of the physical system into ordinary differential equations (ODEs) with a finite number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant-k Filter
Constant k filters, also k-type filters, are a type of electronic filter designed using the image method. They are the original and simplest filters produced by this methodology and consist of a ladder network of identical sections of passive components. Historically, they are the first filters that could approach the ideal filter frequency response to within any prescribed limit with the addition of a sufficient number of sections. However, they are rarely considered for a modern design, the principles behind them having been superseded by other methodologies which are more accurate in their prediction of filter response. History Constant k filters were invented by George Campbell. He published his work in 1922, but had clearly invented the filters some time before, as his colleague at AT&T Co, Otto Zobel, was already making improvements to the design at this time. Campbell's filters were far superior to the simpler single element circuits that had been used previously. Cam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandpass
A band-pass filter or bandpass filter (BPF) is a device that passes frequencies within a certain range and rejects ( attenuates) frequencies outside that range. It is the inverse of a '' band-stop filter''. Description In electronics and signal processing, a filter is usually a two-port circuit or device which removes frequency components of a signal (an alternating voltage or current). A band-pass filter allows through components in a specified band of frequencies, called its '' passband'' but blocks components with frequencies above or below this band. This contrasts with a high-pass filter, which allows through components with frequencies above a specific frequency, and a low-pass filter, which allows through components with frequencies below a specific frequency. In digital signal processing, in which signals represented by digital numbers are processed by computer programs, a band-pass filter is a computer algorithm that performs the same function. The term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RL Circuit
A resistor–inductor circuit (RL circuit), or RL filter or RL network, is an electric circuit composed of resistors and inductors driven by a voltage or current source. A first-order RL circuit is composed of one resistor and one inductor, either in series driven by a voltage source or in parallel driven by a current source. It is one of the simplest analogue infinite impulse response electronic filters. Introduction The fundamental passive linear circuit elements are the resistor (R), capacitor (C) and inductor (L). They can be combined to form the RC circuit, the RL circuit, the LC circuit and the RLC circuit, with the abbreviations indicating which components are used. These circuits exhibit important types of behaviour that are fundamental to analogue electronics. In particular, they are able to act as passive filters. Capacitors are usually preferred to inductors since they can be more easily manufactured and are generally physically smaller, particularly for higher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RC Circuit
A resistor–capacitor circuit (RC circuit), or RC filter or RC network, is an electric circuit composed of resistors and capacitors. It may be driven by a voltage source, voltage or current source and these will produce different responses. A first order RC circuit is composed of one resistor and one capacitor and is the simplest type of RC circuit. RC circuits can be used to filter a signal by blocking certain frequencies and passing others. The two most common RC filters are the high-pass filters and low-pass filters; band-pass filters and band-stop filters usually require RLC filters, though crude ones can be made with RC filters. Natural response The simplest RC circuit consists of a resistor with Electric resistance, resistance and a charged capacitor with capacitance connected to one another in a single loop, without an external voltage source. The capacitor will discharge its stored energy through the resistor. If is taken to be the voltage of the capacitor's top pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
