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Early Completion
Early completion is a property of some classes of asynchronous circuit. It means that the output of a electrical network, circuit may be available as soon as sufficient inputs have arrived to allow it to be determined. For example, if all of the inputs to a multiplexer, mux have arrived, and all are the same, but the select line has not yet arrived, the circuit can still produce an output. Since all the inputs are identical, the select line is irrelevant. Example: an asynchronous ripple-carry adder A Adder (electronics), ripple carry adder is a simple adder circuit, but slow because the carry signal has to propagate through each stage of the adder: This diagram shows a 5-bit ripple carry adder in action. There is a five-stage long carry path, so every time two numbers are added with this adder, it needs to wait for the carry to propagate through all five stages. By switching to dual-rail signalling for the carry bit, it can have each stage signal its carry out as soon as it kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asynchronous Circuit
Asynchronous circuit (clockless or self-timed circuit) is a sequential digital logic circuit that does not use a global clock circuit or signal generator to synchronize its components. Instead, the components are driven by a handshaking circuit which indicates a completion of a set of instructions. Handshaking works by simple data transfer protocols. Many synchronous circuits were developed in early 1950s as part of bigger asynchronous systems (e.g. ORDVAC). Asynchronous circuits and theory surrounding is a part of several steps in integrated circuit design, a field of digital electronics engineering. Asynchronous circuits are contrasted with synchronous circuits, in which changes to the signal values in the circuit are triggered by repetitive pulses called a clock signal. Most digital devices today use synchronous circuits. However asynchronous circuits have a potential to be much faster, have a lower level of power consumption, electromagnetic interference, and better modula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Network
An electrical network is an interconnection of electrical components (e.g., batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage sources, current sources, resistances, inductances, capacitances). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. Linear electrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines), have the property that signals are linearly superimposable. They are thus more easily analyzed, using powerful frequency domain methods such as Laplace transforms, to determine DC response, AC response, and transient response. A resistive circuit is a circuit containing only resistors and ideal current and voltage sources. Analysis of resistive circuits is less complic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplexer
In electronics, a multiplexer (or mux; spelled sometimes as multiplexor), also known as a data selector, is a device that selects between several analog or digital input signals and forwards the selected input to a single output line. The selection is directed by a separate set of digital inputs known as select lines. A multiplexer of 2^n inputs has n select lines, which are used to select which input line to send to the output. A multiplexer makes it possible for several input signals to share one device or resource, for example, one analog-to-digital converter or one communications transmission medium, instead of having one device per input signal. Multiplexers can also be used to implement Boolean functions of multiple variables. Conversely, a demultiplexer (or demux) is a device taking a single input and selecting signals of the output of the compatible mux, which is connected to the single input, and a shared selection line. A multiplexer is often used with a complementa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adder (electronics)
An adder, or summer, is a digital circuit that performs addition of numbers. In many computers and other kinds of processors adders are used in the arithmetic logic units (ALUs). They are also used in other parts of the processor, where they are used to calculate addresses, table indices, increment and decrement operators and similar operations. Although adders can be constructed for many number representations, such as binary-coded decimal or excess-3, the most common adders operate on binary numbers. In cases where two's complement or ones' complement is being used to represent negative numbers, it is trivial to modify an adder into an adder–subtractor. Other signed number representations require more logic around the basic adder. Binary adders Half adder The half adder adds two single binary digits ''A'' and ''B''. It has two outputs, sum (''S'') and carry (''C''). The carry signal represents an overflow into the next digit of a multi-digit addition. The value of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dirca
''Dirca'' is a genus of three or four species of flowering plants in the family Thymelaeaceae, native to North America. The genus is named after Dirce in Greek mythology. The general common name for this deciduous shrub is leatherwood; other names include moosewood, ropebark and the Powhatan-derived name wicopy. The stems of ''Dirca'' are exceptionally pliable and the bark is difficult to tear by hand; for this reason, its stems were used by Native Americans in eastern North America as thongs or ropes. Members of the genus can grow to a maximum height of about three meters, and are often associated with rich, moist woods or slopes above creeks or streams. '' D. palustris'' is a widespread species that grows in scattered populations throughout eastern North America, from Nova Scotia west to North Dakota and Oklahoma, and south to Florida. '' D. occidentalis'' grows in several counties in the San Francisco Bay area of California. '' D. mexicana'' was described in 1995 from one p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carry Look-ahead Adder
A carry-lookahead adder (CLA) or fast adder is a type of electronics adder used in digital logic. A carry-lookahead adder improves speed by reducing the amount of time required to determine carry bits. It can be contrasted with the simpler, but usually slower, ripple-carry adder (RCA), for which the carry bit is calculated alongside the sum bit, and each stage must wait until the previous carry bit has been calculated to begin calculating its own sum bit and carry bit. The carry-lookahead adder calculates one or more carry bits before the sum, which reduces the wait time to calculate the result of the larger-value bits of the adder. Already in the mid 1800s, Charles Babbage recognized the performance penalty imposed by the ripple-carry used in his Difference Engine, and subsequently designed mechanisms for ''anticipating carriage'' for his (never-built) Analytical Engine. Konrad Zuse is thought to have implemented the first carry-lookahead adder in his 1930s binary mechanical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
