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Keyboard Matrix Circuit
A keyboard matrix circuit is a design used in most electronic musical keyboards and computer keyboards in which the key switches are connected by a grid of wires, similar to a diode matrix. For example, 16 wires arranged in 8 rows and 8 columns can connect 64 keys—sufficient for a full five octaves of range (61 notes). By scanning these crossings, a keyboard controller can determine which keys are currently pressed. Description Without a matrix circuit, a 61-key keyboard for a synthesizer, electronic organ, or digital piano would require 62 wires to connect (one for each note, and a ground)—an awkwardly thick bundle of wiring. With a matrix circuit, any of 61 notes can be determined with only 16 wires. This is drawn schematically as a matrix of 8 columns and 8 rows of wires, with a switch at every intersection. The keyboard controller scans the columns. If a key has been pressed, the controller scans the rows—and in a manner analogous to the board game Battleship, the con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Musical Keyboard
A musical keyboard is the set of adjacent depressible levers or keys on a musical instrument. Keyboards typically contain keys for playing the twelve notes of the Western musical scale, with a combination of larger, longer keys and smaller, shorter keys that repeats at the interval of an octave. Pressing a key on the keyboard makes the instrument produce sounds—either by mechanically striking a string or tine ( acoustic and electric piano, clavichord), plucking a string (harpsichord), causing air to flow through a pipe organ, striking a bell (carillon), or, on electric and electronic keyboards, completing a circuit ( Hammond organ, digital piano, synthesizer). Since the most commonly encountered keyboard instrument is the piano, the keyboard layout is often referred to as the ''piano keyboard''. Description The twelve notes of the Western musical scale are laid out with the lowest note on the left. The longer keys (for the seven "natural" notes of the C major scale: C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Modifier Key
In computing, a modifier key is a special key (or combination) on a computer keyboard that temporarily modifies the normal action of another key when pressed together. By themselves, modifier keys usually do nothing; that is, pressing any of the , , or keys alone does not (generally) trigger any action from the computer. For example, in most keyboard layouts the Shift key combination will produce a capital letter "A" instead of the default lower-case letter "a" (unless in Caps lock or Shift lock mode). A combination of in Microsoft Windows will close the active window; in this instance, Alt is the modifier key. In contrast, pressing just or will probably do nothing unless assigned a specific function in a particular program (for example, activating input aids or the toolbar of the active window in Windows). User interface expert Jef Raskin coined the term " quasimode" to describe the state a computer enters into when a modifier key is pressed. Modifier keys on personal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Synthesizer Electronics
A synthesizer (also spelled synthesiser) is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis and frequency modulation synthesis. These sounds may be altered by components such as filters, which cut or boost frequencies; envelopes, which control articulation, or how notes begin and end; and low-frequency oscillators, which modulate parameters such as pitch, volume, or filter characteristics affecting timbre. Synthesizers are typically played with keyboards or controlled by sequencers, software or other instruments, and may be synchronized to other equipment via MIDI. Synthesizer-like instruments emerged in the United States in the mid-20th century with instruments such as the RCA Mark II, which was controlled with punch cards and used hundreds of vacuum tubes. The Moog synthesizer, developed by Robert Moog and first sold in 1964 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Polyphony (instrument)
Polyphony is a property of musical instruments that means that they can play multiple independent melody lines simultaneously. Instruments featuring polyphony are said to be polyphonic. Instruments that are not capable of polyphony are monophonic or paraphonic. Synthesizer Monophonic A monophonic synthesizer or ''monosynth'' is a synthesizer that produces only one note at a time, making it smaller and cheaper than a polyphonic synthesizer which can play multiple notes at once. This does not necessarily refer to a synthesizer with a single oscillator; The Minimoog, for example, has three oscillators which are settable in arbitrary intervals, but it can play only one note at a time. Well-known monosynths include the Minimoog, the Roland TB-303, the Korg Prophecy, and the Korg Monologue. Duophonic Duophonic synthesizers, such as the ARP Odyssey and Formanta Polivoks built in the 1970s and 1980s respectively, have a capability to independently play two pitches at a tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Crossbar Switch
In electronics and telecommunications, a crossbar switch (cross-point switch, matrix switch) is a collection of switches arranged in a matrix configuration. A crossbar switch has multiple input and output lines that form a crossed pattern of interconnecting lines between which a connection may be established by closing a switch located at each intersection, the elements of the matrix. Originally, a crossbar switch consisted literally of crossing metal bars that provided the input and output paths. Later implementations achieved the same switching topology in solid-state electronics. The crossbar switch is one of the principal telephone exchange architectures, together with a rotary switch, memory switch, and a crossover switch. General properties A crossbar switch is an assembly of individual switches between a set of inputs and a set of outputs. The switches are arranged in a matrix. If the crossbar switch has M inputs and N outputs, then a crossbar has a matrix with ''M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Charlieplexing
Charlieplexing (also known as tristate multiplexing, reduced pin-count LED multiplexing, complementary LED drive and crossplexing) is a technique for driving a multiplexed display in which relatively few general-purpose input/output, I/O pins on a microcontroller are used e.g. to drive an array of light emitting diode, LEDs. The method uses the tri-state logic capabilities of microcontrollers in order to gain efficiency over traditional multiplexing. Although it is more efficient in its use of I/O, there are issues that cause it to be more complicated to design and render it difficult for larger displays. These issues include duty cycle, current requirements and the forward voltages of the LEDs. As with any multiplexing, there is a requirement to cycle through the in-use LEDs rapidly so that the persistence of the human eye perceives the display to be lit as a whole. Multiplexing can generally be seen by a strobing effect and skewing if the eye's focal point is moved past the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Multiplexed Display
Multiplexed displays are electronic display devices where the entire display is not driven at one time. Instead, sub-units of the display (typically, rows or columns for a dot matrix display or individual characters for a character oriented display, occasionally individual display elements) are multiplexed, that is, driven one at a time, but the high switching frequency and the persistence of vision combine to make the viewer believe the entire display is continuously active. A multiplexed display has several advantages compared to a non-multiplexed display: * fewer wires (often, far fewer wires) are needed * simpler driving electronics can be used * both lead to reduced cost * reduced power consumption Multiplexed displays can be divided into two broad categories: # character-oriented displays # pixel-oriented displays Character-oriented displays Most character-oriented displays (such as seven-segment displays, fourteen-segment displays, and sixteen-segment displays) display ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Pinball
Pinball games are a family of games in which a ball is propelled into a specially designed table where it bounces off various obstacles, scoring points either en route or when it comes to rest. Historically the board was studded with nails called 'pins' and had hollows or pockets which scored points if the ball came to rest in them. Today, pinball is most commonly an arcade game in which the ball is fired into a specially designed cabinet known as a pinball machine, hitting various lights, bumpers, ramps, and other targets depending on its design. The game's object is generally to score as many points as possible by hitting these targets and making various shots with flippers before the ball is lost. Most pinball machines use one ball per turn (except during special multi-ball phases), and the game ends when the ball(s) from the last turn are lost. The biggest pinball machine manufacturers historically include Bally Manufacturing, Gottlieb, Williams Electronics and Stern Pinball ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Rollover (key)
Key rollover is the ability of a computer keyboard to correctly handle several simultaneous keystrokes. A keyboard with ''n''-key rollover (NKRO) can correctly detect input from each key on the keyboard at the same time, regardless of how many other keys are also being pressed. Keyboards that lack full rollover will register an incorrect keystroke when certain combinations of keys are pressed simultaneously. Rollover has applications for stenotype, electronic music keyboards, gaming, and touch-typing generally. Keyboard usage During normal typing on a conventional computer keyboard, only one key is usually pressed at any given time, then released before the next key is pressed. However, this is not always the case. When using modifier keys such as Shift or Control, the user intentionally holds the modifier key(s) while pressing and releasing another key. * Rapid typists may also sometimes inadvertently press a key before releasing the previous one. Certain unusual forms of keyboa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Computer Keyboard
A computer keyboard is a peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches. Replacing early punched cards and paper tape technology, interaction via teleprinter-style keyboards have been the main input method for computers since the 1970s, supplemented by the computer mouse since the 1980s. Keyboard keys (buttons) typically have a set of characters engraved or printed on them, and each press of a key typically corresponds to a single written symbol. However, producing some symbols may require pressing and holding several keys simultaneously or in sequence. While most keys produce characters ( letters, numbers or symbols), other keys (such as the escape key) can prompt the computer to execute system commands. In a modern computer, the interpretation of key presses is generally left to the software: the information sent to the computer, the scan code, tells it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Diode
A diode is a two- terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used. Among many uses, diodes are found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |