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Built-in Self-test
A built-in self-test (BIST) or built-in test (BIT) is a mechanism that permits a machine to test itself. Engineers design BISTs to meet requirements such as: *high reliability *lower repair cycle times or constraints such as: *limited technician accessibility *cost of testing during manufacture The main purpose of BIST is to reduce the complexity, and thereby decrease the cost and reduce reliance upon external (pattern-programmed) test equipment. BIST reduces cost in two ways: # reduces test-cycle duration # reduces the complexity of the test/probe setup, by reducing the number of I/O signals that must be driven/examined under tester control. Both lead to a reduction in hourly charges for automated test equipment (ATE) service. Applications BIST is commonly placed in weapons, avionics, medical devices, automotive electronics, complex machinery of all types, unattended machinery of all types, and integrated circuits. Automotive Automotive tests itself to enhance safety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Reliability Engineering
Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability is defined as the probability that a product, system, or service will perform its intended function adequately for a specified period of time, OR will operate in a defined environment without failure. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment or interval of time. The ''reliability function'' is theoretically defined as the probability of success. In practice, it is calculated using different techniques, and its value ranges between 0 and 1, where 0 indicates no probability of success while 1 indicates definite success. This probability is estimated from detailed (physics of failure) analysis, previous data sets, or through reliability testing and reliability modeling. Availability, testability, maintainability, and maintenance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Loop Back
Loopback (also written loop-back) is the routing of electronic signals or digital data streams back to their source without intentional processing or modification. It is primarily a means of testing the communications infrastructure. Loopback can take the form of communication channels with only one communication endpoint. Any message transmitted by such a channel is immediately and only received by that same channel. In telecommunications, loopback devices perform transmission tests of access lines from the serving switching center, which usually does not require the assistance of personnel at the served terminal. Loop around is a method of testing between stations that are not necessarily adjacent, wherein two lines are used, with the test being done at one station and the two lines are interconnected at the distant station. A patch cable may also function as loopback, when applied manually or automatically, remotely or locally, facilitating a loop-back test. Where a sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Test Equipment
Test equipment is a general term describing equipment used in many fields. Types of test equipment include: Electrical and electronic test equipment Electrical test equipment * Battery tester, used to test the state of an electric battery * Continuity tester, used to determine if an electrical path can be established between two points ** Cable tester, used to verify the electrical connections in a signal cable or other wired assembly ** Receptacle tester, used to verify that an AC wall outlet is wired properly **Test light A test light, test lamp, voltage tester, or mains tester is a piece of electronic test equipment used to determine the presence of electricity in a piece of equipment under test. A test light is simpler and less costly than a measuring instrumen ..., used to determine the presence or absence of an electric voltage * Hipot tester, used to verify electrical insulation in finished products carrying high electrical potential Electronic test equipment {{see also, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Watchdog Timer
A watchdog timer (WDT, or simply a ''watchdog''), sometimes called a ''computer operating properly timer'' (''COP timer''), is an electronic or software timer that is used to detect and recover from computer malfunctions. Watchdog timers are widely used in computers to facilitate automatic correction of temporary hardware faults, and to prevent errant or malevolent software from disrupting system operation. During normal operation, the computer regularly restarts the watchdog timer to prevent it from elapsing, or ''timeout (computing), timing out''. If, due to a hardware fault or program error, the computer fails to restart the watchdog, the timer will elapse and generate a timeout signal. The timeout signal is used to initiate corrective actions. The corrective actions typically include placing the computer and associated hardware in a safe state and invoking a computer reboot. Microcontrollers often include an integrated, on-chip watchdog. In other computers the watchdog may re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Safety Engineering
Safety engineering is an engineering Branches of science, discipline which assures that engineered systems provide acceptable levels of safety. It is strongly related to industrial engineering/systems engineering, and the subset system safety engineering. Safety engineering assures that a life-critical system behaves as needed, even when components Failure, fail. Analysis techniques Analysis techniques can be split into two categories: Qualitative research, qualitative and Quantitative research, quantitative methods. Both approaches share the goal of finding causal dependencies between a hazard on system level and failures of individual components. Qualitative approaches focus on the question "What must go wrong, such that a system hazard may occur?", while quantitative methods aim at providing estimations about probabilities, rates and/or severity of consequences. The complexity of the technical systems such as Improvements of Design and Materials, Planned Inspections, Fool-pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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System Engineering
Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their Enterprise life cycle, life cycles. At its core, systems engineering utilizes systems thinking principles to organize this body of knowledge. The individual outcome of such efforts, an engineered system, can be defined as a combination of components that work in synergy to collectively perform a useful Function (engineering), function. Issues such as requirements engineering, Reliability engineering, reliability, logistics, coordination of different teams, testing and evaluation, maintainability, and many other Discipline (academia), disciplines, aka List of system quality attributes, "ilities", necessary for successful system design, development, implementation, and ultimate decommission become more difficult when dealing with large or complex projects. Systems engineering deals with work processes, optimizat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Embedded System
An embedded system is a specialized computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is embedded as part of a complete device often including electrical or electronic hardware and mechanical parts. Because an embedded system typically controls physical operations of the machine that it is embedded within, it often has real-time computing constraints. Embedded systems control many devices in common use. , it was estimated that ninety-eight percent of all microprocessors manufactured were used in embedded systems. Modern embedded systems are often based on microcontrollers (i.e. microprocessors with integrated memory and peripheral interfaces), but ordinary microprocessors (using external chips for memory and peripheral interface circuits) are also common, especially in more complex systems. In either case, the processor(s) us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Built-in Test Equipment
Built-in test equipment (BITE) for avionics primarily refers to passive fault management and diagnosis equipment built into airborne systems to support maintenance processes. Built-in test equipment includes multimeter A multimeter (also known as a multi-tester, volt-ohm-milliammeter, volt-ohmmeter or VOM, avometer or ampere-volt-ohmmeter) is a measuring instrument that can measure multiple electrical properties. A typical multimeter can measure voltage, elec ...s, oscilloscopes, discharge probes, and frequency generators that are provided as part of the system to enable testing and perform diagnostics. The acronym BIT is often used for this same function or, more specifically, in reference to the individual tests. BIT often includes: * The detection of the fault * The accommodation of the fault (how the system actively responds to the fault) * The annunciation or logging of the fault to warn of possible effects and/or aid in troubleshooting the faulty equipment. Functiona ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Hardware-in-the-loop
Hardware-in-the-loop (HIL) simulation, also known by various acronyms such as HiL, HITL, and HWIL, is a technique that is used in the development and testing of complex real-time embedded systems. HIL simulation provides an effective testing platform by adding the complexity of the process-actuator system, known as a plant, to the test platform. The complexity of the plant under control is included in testing and development by adding a mathematical representation of all related dynamic systems. These mathematical representations are referred to as the "plant simulation". The embedded system to be tested interacts with this plant simulation. How HIL works HIL simulation must include electrical emulation of sensors and actuators. These electrical emulations act as the interface between the plant simulation and the embedded system under test. The value of each electrically emulated sensor is controlled by the plant simulation and is read by the embedded system under test (feedback) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Simulation
A simulation is an imitative representation of a process or system that could exist in the real world. In this broad sense, simulation can often be used interchangeably with model. Sometimes a clear distinction between the two terms is made, in which simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Another way to distinguish between the terms is to define simulation as experimentation with the help of a model. This definition includes time-independent simulations. Often, computer simulation, computers are used to execute the simulation. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games. Simulation is also used with scientific modelling of natural systems or human systems to gain insight into their functio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Logic Built-in Self-test
Logic built-in self-test (or LBIST) is a form of built-in self-test (BIST) in which hardware and/or software is built into integrated circuits allowing them to test their own operation, as opposed to reliance on external automated test equipment. Advantages The main advantage of LBIST is the ability to test internal circuits having no direct connections to external pins, and thus unreachable by external automated test equipment. Another advantage is the ability to trigger the LBIST of an integrated circuit while running a built-in self test or power-on self test of the finished product. Disadvantages LBIST that requires additional circuitry (or read-only memory) increases the cost of the integrated circuit. LBIST that only requires temporary changes to programmable logic or rewritable memory avoids this extra cost, but requires more time to first program in the BIST and then to remove it and program in the final configuration. Another disadvantage of LBIST is the possibility tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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PBIST
Programmable Built-In Self-Test (PBIST) is a memory DFT feature that incorporates all the required test systems into the chip itself. The test systems implemented on-chip are as follows: * algorithmic address generator * algorithmic data generator * program storage unit * loop control mechanisms PBIST was originally adopted by large memory chips that have high pin counts and operate at high frequencies, thereby exceeding the capability of production testers. The purpose of PBIST is to avoid developing and buying more sophisticated and very expensive testers. The interface between PBIST, which is internal to the processor, and the external tester environment is through the standard JTAG TAP controller pins. Algorithms and controls are fed into the chip through the TAP controller's Test Data Input (TDI) pin. The final result of the PBIST test is read out through the Test Data Output (TDO) pin. PBIST supports the entire algorithmic memory testing requirements imposed by the productio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |