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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 digital piano or a computer keyboard might require 62 wires to connect (one for each key, and a ground)—an awkwardly thick bundle of wiring. With a matrix circuit, any of 61 keys 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, determines the row-column combination at which a key has been pressed, and genera ... [...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 activating an electronic circuit (synthesizer, digital piano, electronic keyboard). Since the most commonly encountered keyboard instrument is the piano, the keyboard layout is often referred to as the piano keyboard or simply piano keys. 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, D, E, F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Keypads
A keypad is a block or pad of buttons set with an arrangement of digits, symbols, or alphabetical letters. Pads mostly containing numbers and used with computers are numeric keypads. Keypads are found on devices which require mainly numeric input such as calculators, television remotes, push-button telephones, vending machines, ATMs, point of sale terminals, combination locks, safes, and digital door locks. Many devices follow the E.161 standard for their arrangement. Uses and functions A computer keyboard usually has a small numeric keypad on the side, in addition to the other number keys on the top, but with a calculator-style arrangement of buttons that allow more efficient entry of numerical data. This number pad (commonly abbreviated to ''numpad'') is usually positioned on the right side of the keyboard because most people are right-handed. Many laptop computers have special function keys that turn part of the alphabetical keyboard into a numerical keypad as there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Synthesizer Electronics
A synthesizer (also synthesiser or synth) 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. An intuitively understandable example for a polyphonic instrument is a (classical) piano, on which the player plays different melody lines with the left and the right hand - depending on music style and composition, these may be musically tightly interrelated or may even be totally unrelated to each other, like in parts of Jazz music. An example for monophonic instruments is a trumpet which can generate only one tone (frequency) at a time, except when played by extraordinary musicians. 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 n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Diode Matrix
A diode matrix is a two-dimensional grid of wires: each "intersection" wherein one-row crosses over another has either a diode A diode is a two-Terminal (electronics), terminal electronic component that conducts electric current primarily in One-way traffic, one direction (asymmetric electrical conductance, conductance). It has low (ideally zero) Electrical resistance ... connecting them, or the wires are isolated from each other. It is one of the popular techniques for implementing a read-only memory. A diode matrix is used as the control store or microprogram in many early computers. A logically equivalent transistor matrix is still used as the control store or microprogram or 'decode ROM' in many modern microprocessors. A single row of the diode matrix (or transistor matrix) is activated at any one instant. Charge flows through each diode connected to that row. That activates the column corresponding to each row. The only activated control signals during that instant w ... [...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 (mathematics), 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 system, 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 ... [...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 accessing a large number of LEDs, switches, micro-capacitors or other I/O entities, using relatively few tri-state logic wires from a microcontroller. These I/O entities can be wired as discrete components, x/y arrays, or woven in a diagonally intersecting pattern to form diagonal arrays. Etymology Although the technique was introduced in 2001 by Maxim Integrated, the name "Charlieplexing", however, first occurred in a 2003 application note. It was named after Charles "Charlie" M. Allen, an applications engineer of MAX232 fame, who had proposed this method internally. How and why to use Charlieplexing The simplest way to address a single pixel (or input button) is to run a wire out to it and another wire back to ground, but this requires a lot of wiring. A slight improvement is to have everything return on a common groun ... [...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 P ... [...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 keyboard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Computer Keyboard
A computer keyboard is a built-in or peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or Push-button, keys to act as Mechanical keyboard, mechanical levers or Electronic switching system, electronic switches. Replacing early punched cards and paper tape technology, interaction via teleprinter-style keyboards have been the main input device, input method for computers since the 1970s, supplemented by the computer mouse since the 1980s, and the touchscreen since the 2000s. Keyboard keys (buttons) typically have a set of characters Engraving, engraved or Printing, 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 character (computing), characters (Letter (alphabet), letters, Numerical digit, numbers or symbols), other keys (such as the escape key) can prompt the ... [...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. They are commonly used in defined sequences of keys with another keys to trigger a specific action. These sequences are called keyboard shortcuts. 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 trigger the shortcut for closing 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 Windo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |