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Impedance Bridging
In audio engineering and sound recording, a high impedance bridging, voltage bridging, or simply bridging connection is one in which the load impedance is much larger than the source impedance. The load measures the source's voltage while minimally drawing current or affecting it. Explanation When the output of a device (consisting of the voltage source ''V''S and output impedance ''Z''S in illustration) is connected to the input of another device (the load impedance ''Z''L in the illustration), these two impedances form a voltage divider: : V_L = \frac V_S \, . One can maximize the signal level ''V''L by using a voltage source whose output impedance ''Z''S is as small as possible and by using a receiving device whose input impedance ''Z''L is as large as possible. When Z_L \gg Z_S (typically by at least ten times), this is called a ''bridging connection'' and has a number of effects including: * Advantages: ** Reduces the 6dB attenuation incurred by impedance matc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Audio Engineering
Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to: Sound *Audio signal, an electrical representation of sound * Audio frequency, a frequency in the audio spectrum *Digital audio, representation of sound in a form processed and/or stored by computers or digital electronics *Audio, audible content (media) in audio production and publishing * Semantic audio, extraction of symbols or meaning from audio * Stereophonic audio, method of sound reproduction that creates an illusion of multi-directional audible perspective * Audio equipment Entertainment * AUDIO (group), an American R&B band of 5 brothers formerly known as TNT Boyz and as B5 * ''Audio'' (album), an album by the Blue Man Group * ''Audio'' (magazine), a magazine published from 1947 to 2000 * Audio (musician), British drum and bass artist * "Audio" (song), a song by LSD *"Audios", a song by Black Eyed Peas from ''Elevation'' Computing * HTML audio, identified by the tag See ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Signal Reflection
In telecommunications, signal reflection happens when a signal is transmitted along a transmission medium (such as a copper cable or an optical fiber) and part of it is reflected back toward the source instead of reaching the end. This reflection is caused by imperfections or physical variations in the cable (such as abrupt changes in its geometry) that lead to impedance mismatches. These mismatches disrupt the signal and cause some of it to bounce back. In radio frequency (RF) systems, this is typically measured using the voltage standing wave ratio (VSWR), with device called a VSWR bridge. The amount of reflected energy depends on the degree of impedance mismatch and is mathematically describe by the reflection coefficient. Because the principles are the same, this concept is perhaps easiest to understand when considering an optical fiber. Imperfections in the glass create mirrors that reflect the light back along the fiber. Impedance discontinuities cause attenuation, attenu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Damping Factor
In an audio system, the damping factor is defined as the ratio of the rated impedance of the loudspeaker (usually assumed to be ) to the Output impedance, source impedance of the power amplifier. It was originally proposed in 1941. Only the magnitude of the loudspeaker impedance is used, and the power amplifier output impedance is assumed to be totally resistive. In typical solid state and tube amplifiers, the damping factor varies as a function of frequency. In solid state amplifiers, the damping factor usually has a maximum value at low frequencies, and it reduces progressively at higher frequencies. The figure to the right shows the damping factor of two amplifiers. One is a solid state amplifier (Luxman L-509u) and the other is a tube amplifier (Rogue Atlas). These results are fairly typical of these two types of amplifiers, and they serve to illustrate the fact that tube amplifiers usually have much lower damping factors than modern solid state amplifiers, which is an undes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Maximum Power Transfer Theorem
In electrical engineering, the maximum power transfer theorem states that, to obtain ''maximum'' external power from a power source with internal resistance, the resistance of the load must equal the resistance of the source as viewed from its output terminals. Moritz von Jacobi published the maximum power (transfer) theorem around 1840; it is also referred to as "Jacobi's law". The theorem results in maximum ''power'' transfer from the power source to the load, but not maximum ''efficiency'' of useful power out of total power consumed. If the load resistance is made larger than the source resistance, then efficiency increases (since a higher percentage of the source power is transferred to the load), but the ''magnitude'' of the load power decreases (since the total circuit resistance increases). If the load resistance is made smaller than the source resistance, then efficiency decreases (since most of the power ends up being dissipated in the source). Although the total powe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Electrical Efficiency
The efficiency of a system in electronics and electrical engineering is defined as useful power output divided by the total electrical power consumed (a vulgar fraction, fractional Expression (mathematics), expression), typically denoted by the Greek alphabet, Greek small letter eta (η – ήτα). : \mathrm=\frac If energy output and input are expressed in the same units, efficiency is a dimensionless number. Where it is not customary or convenient to represent input and output energy in the same units, efficiency-like quantities have units associated with them. For example, the heat rate (efficiency), heat rate of a fossil fuel power station, fossil fuel power plant may be expressed in British thermal unit, BTU per kilowatt-hour. Luminous efficacy of a light source expresses the amount of visible light for a certain amount of power transfer and has the units of lumen (unit), lumens per watt. Efficiency of typical electrical devices ''Efficiency'' should not be confused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Maximum Power Transfer Graph
In mathematical analysis, the maximum and minimum of a function (mathematics), function are, respectively, the greatest and least value taken by the function. Known generically as extremum, they may be defined either within a given Interval (mathematics), range (the ''local'' or ''relative'' extrema) or on the entire domain of a function, domain (the ''global'' or ''absolute'' extrema) of a function. Pierre de Fermat was one of the first mathematicians to propose a general technique, adequality, for finding the maxima and minima of functions. As defined in set theory, the maximum and minimum of a set (mathematics), set are the greatest and least elements in the set, respectively. Unbounded infinite sets, such as the set of real numbers, have no minimum or maximum. In statistics, the corresponding concept is the sample maximum and minimum. Definition A real-valued Function (mathematics), function ''f'' defined on a Domain of a function, domain ''X'' has a global (or absolute) m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Balanced Audio
Balanced audio is a method of interconnecting audio equipment using balanced interfaces. This type of connection is very important in sound recording and production because it allows the use of long cables while reducing susceptibility to external noise caused by electromagnetic interference. The balanced interface guarantees that induced noise appears as common-mode voltages at the receiver which can be rejected by a differential device. Balanced connections typically use shielded twisted-pair cable and three-conductor connectors. The connectors are usually three-pin XLR or TRS phone connectors. When used in this manner, each cable carries one channel, therefore stereo audio (for example) would require two of them. A common misconception is that balanced audio requires the signal source to deliver equal waveforms of opposite polarity to the two signal conductors of the balanced line. However, many balanced devices actively drive only one side of the line, but do so at an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
DI Box
A DI unit (direct input or direct inject) is an electronic device typically used in recording studios and in sound reinforcement systems to connect a high output impedance unbalanced output signal to a low-impedance, microphone level, balanced input, usually via an XLR connector and XLR cable. DIs are frequently used to connect an electric guitar or electric bass to a mixing console's microphone input jack. Its signal comes "direct" from the source instrument without passing through the air as sound waves, and thus is isolated from other sounds and avoids effects of microphone or room acoustics. The DI performs level matching, balancing, and either active buffering or passive impedance matching or impedance bridging. DI units are typically metal boxes with input and output jacks and, for more expensive units, “ground lift” and attenuator switches. DI boxes are extensively used with professional and semi-professional PA systems, professional sound reinforcement systems and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pickup (music Technology)
A pickup is an electronic device that converts energy from one form to another that captures or senses mechanical vibrations produced by musical instruments, particularly stringed instruments such as the electric guitar, and converts these to an electrical signal that is amplified using an instrument amplifier to produce musical sounds through a loudspeaker in a speaker enclosure. The signal from a pickup can also be recorded directly. The first electrical string instrument with pickups, the " Frying Pan" slide guitar, was created by George Beauchamp and Adolph Rickenbacker around 1931. Most electric guitars and electric basses use magnetic pickups. Acoustic guitars, upright basses and fiddles often use a piezo electric pickup. Magnetic pickups A typical magnetic pickup is a transducer (specifically a variable reluctance sensor) that consists of one or more permanent magnets (usually alnico or ferrite) wrapped with a coil of several thousand turns of fine enameled ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Vacuum Tube
A vacuum tube, electron tube, thermionic valve (British usage), or tube (North America) is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. It takes the form of an evacuated tubular envelope of glass or sometimes metal containing electrodes connected to external connection pins. The type known as a thermionic tube or thermionic valve utilizes thermionic emission of electrons from a hot cathode for fundamental Electronics, electronic functions such as signal amplifier, amplification and current Rectifier, rectification. Non-thermionic types such as vacuum phototubes achieve electron emission through the photoelectric effect, and are used for such purposes as the detection of light and measurement of its intensity. In both types the electrons are accelerated from the cathode to the anode by the electric field in the tube. The first, and simplest, vacuum tube, the diode or Flem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Operational Amplifier
An operational amplifier (often op amp or opamp) is a direct coupling, DC-coupled Electronic component, electronic voltage amplifier with a differential input, a (usually) Single-ended signaling, single-ended output, and an extremely high gain (electronics), gain. Its name comes from its original use of performing mathematical operations in analog computers. By using negative feedback, an Op amp circuits, op amp circuit's characteristics (e.g. its gain, input and output impedance, bandwidth (signal processing), bandwidth, and functionality) can be determined by external components and have little dependence on temperature coefficients or engineering tolerance in the op amp itself. This flexibility has made the op amp a popular building block in analog circuits. Today, op amps are used widely in consumer, industrial, and scientific electronics. Many standard integrated circuit op amps cost only a few cents; however, some integrated or hybrid operational amplifiers with special p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Microphone
A microphone, colloquially called a mic (), or mike, is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers and other electronic devices, such as mobile phones, for recording sounds, speech recognition, Voice over IP, VoIP, and other purposes, such as Ultrasonic transducer, ultrasonic sensors or knock sensors. Several types of microphone are used today, which employ different methods to convert the air pressure variations of a sound wave to an electrical signal. The most common are the dynamic microphone, which uses a coil of wire suspended in a magnetic field; the condenser microphone, which uses the vibrating Diaphragm (acoustics), diaphragm as a capacitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
