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Constant Fraction Discriminator
A constant fraction discriminator (CFD) is an electronic signal processing device, designed to mimic the mathematical operation of finding a maximum of a pulse by finding the zero of its slope. Some signals do not have a sharp maximum, but short rise times t_r. Typical input signals for CFDs are pulses from plastic scintillation counters, such as those used for lifetime measurement in positron annihilation experiments. The scintillator pulses have identical rise times that are much longer than the desired temporal resolution. This forbids simple threshold triggering, which causes a dependence of the trigger time on the signal's peak height, an effect called ''time walk'' (see diagram). Identical rise times and peak shapes permit triggering not on a fixed threshold but on a ''constant fraction'' of the total peak height, yielding trigger times independent from peak heights. From another point of view A time-to-digital converter assigns timestamps. The time-to-digital converte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant Fraction 1
Constant or The Constant may refer to: Mathematics * Constant (mathematics), a non-varying value * Mathematical constant, a special number that arises naturally in mathematics, such as or Other concepts * Control variable or scientific constant, in experimentation the unchanging or constant variable * Physical constant, a physical quantity generally believed to be universal and unchanging * Constant (computer programming), a value that, unlike a variable, cannot be reassociated with a different value * Logical constant, a symbol in symbolic logic that has the same meaning in all models, such as the symbol "=" for "equals" People * Constant (given name) * Constant (surname) * John, Elector of Saxony (1468–1532), known as John the Constant * Constant Nieuwenhuys (1920-2005), better known as Constant Places * Constant, Barbados, a populated place Arts and entertainment * " The Constant", a 2008 episode of the television show ''Lost'' * ''The Constant'' (Story of the Year a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxima And Minima
In mathematical analysis, the maximum and minimum of a function are, respectively, the greatest and least value taken by the function. Known generically as extremum, they may be defined either within a given range (the ''local'' or ''relative'' extrema) or on the entire domain (the ''global'' or ''absolute'' extrema) of a function. Pierre de Fermat was one of the first mathematicians to propose a general technique, adequality, for finding the maxima and minima of functions. As defined in set theory, the maximum and minimum of a set are the greatest and least elements in the set, respectively. Unbounded infinite sets, such as the set of real numbers, have no minimum or maximum. In statistics, the corresponding concept is the sample maximum and minimum. Definition A real-valued function ''f'' defined on a domain ''X'' has a global (or absolute) maximum point at ''x''∗, if for all ''x'' in ''X''. Similarly, the function has a global (or absolute) minimum point at ''x''� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slope
In mathematics, the slope or gradient of a Line (mathematics), line is a number that describes the direction (geometry), direction of the line on a plane (geometry), plane. Often denoted by the letter ''m'', slope is calculated as the ratio of the vertical change to the horizontal change ("rise over run") between two distinct points on the line, giving the same number for any choice of points. The line may be physical – as set by a Surveying, road surveyor, pictorial as in a diagram of a road or roof, or Pure mathematics, abstract. An application of the mathematical concept is found in the grade (slope), grade or gradient in geography and civil engineering. The ''steepness'', incline, or grade of a line is the absolute value of its slope: greater absolute value indicates a steeper line. The line trend is defined as follows: *An "increasing" or "ascending" line goes from left to right and has positive slope: m>0. *A "decreasing" or "descending" line goes from left to right ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scintillation Counter
A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the Electron excitation, excitation effect of incident radiation on a Scintillation (physics), scintillating material, and detecting the resultant light pulses. It consists of a scintillator which generates photons in response to incident radiation, a sensitive photodetector (usually a photomultiplier tube (PMT), a charge-coupled device (CCD) camera, or a photodiode), which converts the light to an electrical signal and electronics to process this signal. Scintillation counters are widely used in radiation protection, assay of radioactive materials and physics research because they can be made inexpensively yet with good quantum efficiency, and can measure both the intensity and the Electronvolt, energy of incident radiation. History The first electronic scintillation counter was invented in 1944 by Samuel Curran, Sir Samuel Curran whilst he was working on the Manhattan Project at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron–positron Annihilation
Electron–positron annihilation occurs when an electron () and a positron (, the electron's antiparticle) collide. At low energies, the result of the collision is the annihilation of the electron and positron, and the creation of energetic photons: : + → + At high energies, other particles, such as B mesons or the W and Z bosons, can be created. All processes must satisfy a number of conservation laws, including: * Conservation of electric charge. The net charge before and after is zero. *Conservation of linear momentum and total energy. This forbids the creation of a single photon. However, in quantum field theory this process is allowed; see examples of annihilation. *Conservation of angular momentum. *Conservation of total (i.e. net) lepton number, which is the number of leptons (such as the electron) minus the number of antileptons (such as the positron); this can be described as a conservation of (net) matter law. As with any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CFD Diagram1
__NOTOC__ CFD may refer to: Business and economics * Centre for Finance and Development in Geneva, Switzerland * Contract for difference, a type of financial derivative * Contracts for Difference (UK energy), market support mechanism for low carbon electricity generation in the UK * Control-flow diagram, of a process * Cumulative flow diagram, in queueing theory Firefighting services * Calgary Fire Department, Alberta, Canada * Chicago Fire Department, Illinois, U.S. * Cleveland Fire Department, Ohio, U.S. * Columbus Fire Department, Ohio, U.S. Science and technology * Common fill device, in cryptography * Complement factor D, an enzyme * Computational fluid dynamics * Congenital Femoral Deficiency, a birth defect * Constant fraction discriminator, a signal processing device * Counterfactual definiteness, a concept in quantum mechanics Transport * Caulfield railway station, Melbourne * Clarkefield railway station, Melbourne * Coulter Field (IATA: CFD), an airport in Br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time-to-digital Converter
In electronic instrumentation and signal processing, a time-to-digital converter (TDC) or time digitizer (TD) is a device for recognizing events and providing a digital representation of the time they occurred. For example, a TDC might output the time of arrival for each incoming pulse. Some applications wish to measure the time interval between two events rather than some notion of an absolute time, and the digitizer is then used to measure a time interval and convert it into digital (binary) output. In some cases, an interpolating TDC is also called a time counter (TC). When TDCs are used to determine the time interval between two signal pulses (known as start and stop pulse), measurement is started and stopped when the rising or falling edge of a signal pulse crosses a set threshold. This pattern is seen in many physical experiments, like time-of-flight and lifetime measurements in atomic and high energy physics, experiments that involve laser ranging and electronic re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplifier
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude (magnitude of the voltage or current) of a signal applied to its input terminals, producing a proportionally greater amplitude signal at its output. The amount of amplification provided by an amplifier is measured by its gain: the ratio of output voltage, current, or power to input. An amplifier is defined as a circuit that has a power gain greater than one. An amplifier can be either a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be categorized in different ways. One is by the frequency of the electronic signal being amplified. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Computer
An analog computer or analogue computer is a type of computation machine (computer) that uses physical phenomena such as Electrical network, electrical, Mechanics, mechanical, or Hydraulics, hydraulic quantities behaving according to the mathematical principles in question (''analog signals'') to Scientific modelling, model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discrete values of both time and amplitude (digital signals). Analog computers can have a very wide range of complexity. Slide rules and nomograms are the simplest, while naval gunfire control computers and large hybrid digital/analog computers were among the most complicated. Complex mechanisms for process control and protective relays used analog computation to perform control and protective functions. Analog computers were widely used in scientific and industrial applications even after the advent of digital computers, because at the time they were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparator
In electronics, a comparator is a device that compares two voltages or currents and outputs a digital signal indicating which is larger. It has two analog input terminals V_+ and V_- and one binary digital output V_\text. The output is ideally : V_\text = \begin 1, & \textV_+ > V_-, \\ 0, & \textV_+ < V_-. \end A comparator consists of a specialized high- gain . They are commonly used in devices that measure and digitize analog signals, such as s (ADCs), as well as [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AND Gate
The AND gate is a basic digital logic gate that implements the logical conjunction (∧) from mathematical logic AND gates behave according to their truth table. A HIGH output (1) results only if all the inputs to the AND gate are HIGH (1). If any of the inputs to the AND gate are not HIGH, a LOW (0) is outputted. The function can be extended to any number of inputs by multiple gates up in a chain. Symbols There are three symbols for AND gates: the American (ANSI or 'military') symbol and the IEC ('European' or 'rectangular') symbol, as well as the deprecated DIN symbol. Additional inputs can be added as needed. For more information see the Logic gate symbols article. It can also be denoted as symbol "^" or "&". The AND gate with inputs ''A'' and ''B'' and output ''C'' implements the logical expression C = A \cdot B. This expression also may be denoted as C=A \wedge B or C=A \And B. As of Unicode 16.0.0, the AND gate is also encoded in the Symbols for Legacy Computing Su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foster–Seeley Discriminator
The Foster–Seeley discriminator is a common type of FM detector circuit, invented in 1936 by Dudley E. Foster and Stuart William Seeley. The Foster–Seeley discriminator was envisioned for automatic frequency control of receivers, but also found application in demodulating an FM signal. The Foster–Seeley discriminator uses a tuned RF transformer to convert frequency changes into amplitude changes. A transformer, tuned to the carrier frequency, is connected to two rectifier diodes. The circuit resembles a full bridge rectifier. The phase of the voltage at the secondary coil depends on whether the carrier is below or above the resonance, resulting in a positive or negative shift, respectively. The circuit makes use of the near-90^\circ phase difference occurring between the voltages in two loosely coupled resonant circuits at the peak frequency. Through the coupling capacitor C_k, the primary voltage is applied to the center tap of the secondary, producing a sum and a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
