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Boxcar Averager
A boxcar averager (alternative names are gated integrator and boxcar integrator) is an electronic test instrument that integrates the signal input voltage after a defined waiting time (trigger delay) over a specified period of time (gate width) and then averages over multiple integration results (samples) – for a mathematical description see boxcar function. The main purpose of this measurement technique is to improve signal to noise ratio in pulsed experiments with often low duty cycle by the following three mechanisms: 1) signal integration acts as a first averaging step that strongly suppresses noise components with a frequency of the reciprocal gate width and higher, 2) time-domain based selection of signal parts that actually carry information of interest and neglect of all signal parts where only noise is present, and 3) averaging over a defined number of periods provides low-pass filtering and convenient adjustment of time resolution. Similar to lock-in amplifiers, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boxcar Averager Block Diagram (general)
A boxcar is the North American (AAR) term for a railroad car that is enclosed and generally used to carry freight. The boxcar, while not the simplest freight car design, is considered one of the most versatile since it can carry most loads. Boxcars have side sliding doors of varying size and operation, and some include end doors and adjustable bulkheads to load very large items. Similar covered freight cars outside North America are covered goods wagons and, depending on the region, are called ''goods van'' ( UK and Australia), ''covered wagon'' ( UIC and UK) or simply ''van'' (UIC, UK and Australia). Use Boxcars can carry most kinds of freight. Originally they were hand-loaded, but in more recent years mechanical assistance such as forklifts have been used to load and empty them faster. Their generalized design is still slower to load and unload than specialized designs of car, and this partially explains the decline in boxcar numbers since World War II. The other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Test Instrument
Electronic test equipment is used to create signals and capture responses from electronic devices under test (DUTs). In this way, the proper operation of the DUT can be proven or faults in the device can be traced. Use of electronic test equipment is essential to any serious work on electronics systems. Practical electronics engineering and assembly requires the use of many different kinds of electronic test equipment ranging from the very simple and inexpensive (such as a test light consisting of just a light bulb and a test lead) to extremely complex and sophisticated such as automatic test equipment (ATE). ATE often includes many of these instruments in real and simulated forms. Generally, more advanced test gear is necessary when developing circuits and systems than is needed when doing production testing or when troubleshooting existing production units in the field. Types of test equipment Basic equipment The following items are used for basic measurement of voltages, cu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral
In mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ..., an integral assigns numbers to functions in a way that describes Displacement (geometry), displacement, area, volume, and other concepts that arise by combining infinitesimal data. The process of finding integrals is called integration. Along with Derivative, differentiation, integration is a fundamental, essential operation of calculus,Integral calculus is a very well established mathematical discipline for which there are many sources. See and , for example. and serves as a tool to solve problems in mathematics and physics involving the area of an arbitrary shape, the length of a curve, and the volume of a solid, among others. The integrals enumerated here are those termed definite integrals, which can be int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boxcar Function
In mathematics, a boxcar function is any function which is zero over the entire real line except for a single interval where it is equal to a constant, ''A''. The boxcar function can be expressed in terms of the uniform distribution as \operatorname(x)= (b-a)A\,f(a,b;x) = A(H(x-a) - H(x-b)), where is the uniform distribution of ''x'' for the interval and H(x) is the Heaviside step function. As with most such discontinuous functions, there is a question of the value at the transition points. These values are probably best chosen for each individual application. When a boxcar function is selected as the impulse response of a filter, the result is a moving average filter. The function is named after its graph's resemblance to a boxcar, a type of railroad car. See also * Boxcar averager * Rectangular function * Step function * Top-hat filter The name Top-hat filter refers to several real-space or Fourier space filtering techniques (not to be confused with the top-hat transf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boxcar Averager UHFLI Zurich Instruments Picture Instrument Front
A boxcar is the North American (AAR) term for a railroad car that is enclosed and generally used to carry freight. The boxcar, while not the simplest freight car design, is considered one of the most versatile since it can carry most loads. Boxcars have side sliding doors of varying size and operation, and some include end doors and adjustable bulkheads to load very large items. Similar covered freight cars outside North America are covered goods wagons and, depending on the region, are called ''goods van'' ( UK and Australia), ''covered wagon'' ( UIC and UK) or simply ''van'' (UIC, UK and Australia). Use Boxcars can carry most kinds of freight. Originally they were hand-loaded, but in more recent years mechanical assistance such as forklifts have been used to load and empty them faster. Their generalized design is still slower to load and unload than specialized designs of car, and this partially explains the decline in boxcar numbers since World War II. The other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duty Cycle
A duty cycle or power cycle is the fraction of one period in which a signal or system is active. Duty cycle is commonly expressed as a percentage or a ratio. A period is the time it takes for a signal to complete an on-and-off cycle. As a formula, a duty cycle (%) may be expressed as: :D = \frac \times 100\% Equally, a duty cycle (ratio) may be expressed as: :D = \frac where D is the duty cycle, PW is the pulse width (pulse active time), and T is the total period of the signal. Thus, a 60% duty cycle means the signal is on 60% of the time but off 40% of the time. The "on time" for a 60% duty cycle could be a fraction of a second, a day, or even a week, depending on the length of the period. Duty cycles can be used to describe the percent time of an active signal in an electrical device such as the power switch in a switching power supply or the firing of action potentials by a living system such as a neuron. The duty factor for periodic signal expresses the same notion, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-pass Filter
A low-pass filter is a filter that passes signals with a frequency lower than a selected cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The exact frequency response of the filter depends on the filter design. The filter is sometimes called a high-cut filter, or treble-cut filter in audio applications. A low-pass filter is the complement of a high-pass filter. In optics, high-pass and low-pass may have different meanings, depending on whether referring to frequency or wavelength of light, since these variables are inversely related. High-pass frequency filters would act as low-pass wavelength filters, and vice versa. For this reason it is a good practice to refer to wavelength filters as ''short-pass'' and ''long-pass'' to avoid confusion, which would correspond to ''high-pass'' and ''low-pass'' frequencies. Low-pass filters exist in many different forms, including electronic circuits such as a hiss filter used in audio, anti-aliasing fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lock-in Amplifier
A lock-in amplifier is a type of amplifier that can extract a signal with a known carrier wave from an extremely noisy environment. Depending on the dynamic reserve of the instrument, signals up to a million times smaller than noise components, potentially fairly close by in frequency, can still be reliably detected. It is essentially a homodyne detector followed by low-pass filter that is often adjustable in cut-off frequency and filter order. The device is often used to measure phase shift, even when the signals are large, have a high signal-to-noise ratio and do not need further improvement. Recovering signals at low signal-to-noise ratios requires a strong, clean reference signal with the same frequency as the received signal. This is not the case in many experiments, so the instrument can recover signals buried in the noise only in a limited set of circumstances. The lock-in amplifier is commonly believed to have been invented by Princeton University physicist Robert H. Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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