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Compatible Discrete 4
Compatible Discrete 4, also known as Quadradisc or CD-4 (not to be confused with compact disc) was a discrete four-channel quadraphonic system for phonograph records. The system was created by JVC and RCA in 1971 and introduced in May 1972. Hundreds of recordings using this technology were released on LP during the 1970s. Other major record companies who adopted this format include A&M, Arista, Atlantic, Capricorn, Elektra, Fantasy, Nonesuch, Reprise and Warner Bros. This was the only discrete quadraphonic phonograph record system to gain major industry acceptance. A competing system, UD-4, was later introduced by Denon ( Nippon Columbia). In discrete quadraphonic systems, all four channels remain fully independent of each other throughout the entire recording and reproduction chain. There is no intermingling of channels as is done in matrix decoder 4-channel systems such as Stereo Quadraphonic (SQ) and QS Regular Matrix. Though CD-4 and other quadraphonic tech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cd4 Logo
In molecular biology, CD4 (cluster of differentiation 4) is a glycoprotein that serves as a co-receptor for the T-cell receptor (TCR). CD4 is found on the surface of immune cells such as helper T cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 (after the OKT4 monoclonal antibody that reacted with it) before being named CD4 in 1984. In humans, the CD4 protein is encoded by the ''CD4'' gene. CD4+ T helper cells are white blood cells that are an essential part of the human immune system. They are often referred to as CD4 cells, T helper cells or T4 cells. They are called helper cells because one of their main roles is to send signals to other types of immune cells, including CD8 killer cells, which then destroy the infectious particle. If CD4 cells become depleted, for example in untreated HIV infection, or following immune suppression prior to a transplant, the body is left vulnerable to a wide ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UD-4
UD-4 was a discrete four-channel quadraphonic sound system for phonograph records introduced by Nippon Columbia (Denon) in 1974. This system had some similarities with the more successful CD-4 process introduced by JVC and RCA in 1972. Only about 35 to 40 LP album titles were encoded in this format, and it was marketed only in the UK, Europe and Japan. Most of these releases were marketed by the Denon label. The UMX (universal matrix) standard used for UD-4 contains two subsystems: *BMX (quadrasonic, two channel matrix), a basic 4-2-4 matrix decoder (different from QS Regular Matrix); *QMX (four channel matrix), a discrete 4-4-4 system (adding band-limited localization information encoded with high frequency carrier signals similar to the CD-4 system). The UD-4 process modulated both BMX and QMX into a single record. This way, a BMX decoder could be used to decode quadraphonic sound using an existing stereo record player, while by using a special phono cartridge and a spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplifier
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude (magnitude of the voltage or current) of a signal applied to its input terminals, producing a proportionally greater amplitude signal at its output. The amount of amplification provided by an amplifier is measured by its gain: the ratio of output voltage, current, or power to input. An amplifier is defined as a circuit that has a power gain greater than one. An amplifier can be either a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be categorized in different ways. One is by the frequency of the electronic signal being amplified. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demodulation
Demodulation is the process of extracting the original information-bearing signal from a carrier wave. A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated carrier wave. There are many types of modulation, and there are many types of demodulators. The signal output from a demodulator may represent sound (an analog audio signal), images (an analog video signal) or binary data (a digital signal). These terms are traditionally used in connection with radio receivers, but many other systems use many kinds of demodulators. For example, in a modem, which is a contraction of the terms modulator/demodulator, a demodulator is used to extract a serial digital data stream from a carrier signal which is used to carry it through a telephone line, coaxial cable, or optical fiber. History Demodulation was first used in radio receivers. In the wireless telegraphy radio systems us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cone
In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the '' apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, or lines connecting a common point, the apex, to all of the points on a base. In the case of line segments, the cone does not extend beyond the base, while in the case of half-lines, it extends infinitely far. In the case of lines, the cone extends infinitely far in both directions from the apex, in which case it is sometimes called a ''double cone''. Each of the two halves of a double cone split at the apex is called a ''nappe''. Depending on the author, the base may be restricted to a circle, any one-dimensional quadratic form in the plane, any closed one-dimensional figure, or any of the above plus all the enclosed points. If the enclosed points are included in the base, the cone is a solid object; otherwise it is an open surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shibata Stylus
A phonograph, later called a gramophone, and since the 1940s a record player, or more recently a turntable, is a device for the mechanical and analogue reproduction of sound. The sound vibration waveforms are recorded as corresponding physical deviations of a helical or spiral groove engraved, etched, incised, or impressed into the surface of a rotating cylinder or disc, called a '' record''. To recreate the sound, the surface is similarly rotated while a playback stylus traces the groove and is therefore vibrated by it, faintly reproducing the recorded sound. In early acoustic phonographs, the stylus vibrated a diaphragm that produced sound waves coupled to the open air through a flaring horn, or directly to the listener's ears through stethoscope-type earphones. The phonograph was invented in 1877 by Thomas Edison; its use would rise the following year. Alexander Graham Bell's Volta Laboratory made several improvements in the 1880s and introduced the graphophone, includin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stylus
A stylus is a writing utensil or tool for scribing or marking into softer materials. Different styluses were used to write in cuneiform by pressing into wet clay, and to scribe or carve into a wax tablet. Very hard styluses are also used to Engraving, engrave metal, and the slate and stylus system is used to punch out dots to write in Braille. Styluses are held in the hand and thus are usually a narrow elongated shape, similar to a modern ballpoint pen. Many styluses are heavily curved to be held more easily. The word ''stylus'' is also used to describe Stylus (computing), computer styluses used to assist in navigating or providing more precision when using touchscreens. Etymology ''Stylus'' comes from the Latin —the spelling ''stylus'' arose from an erroneous connection with Greek (), 'pillar'.''Oxford Latin Dictionary'', s.v. "stilus" (2012). The Latin word had several meanings, including "a long, sharply pointed piece of metal; the stem of a plant; a pointed instrume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellipse
In mathematics, an ellipse is a plane curve surrounding two focus (geometry), focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special type of ellipse in which the two focal points are the same. The elongation of an ellipse is measured by its eccentricity (mathematics), eccentricity e, a number ranging from e = 0 (the Limiting case (mathematics), limiting case of a circle) to e = 1 (the limiting case of infinite elongation, no longer an ellipse but a parabola). An ellipse has a simple algebraic solution for its area, but for Perimeter of an ellipse, its perimeter (also known as circumference), Integral, integration is required to obtain an exact solution. The largest and smallest diameters of an ellipse, also known as its width and height, are typically denoted and . An ellipse has four extreme points: two ''Vertex (geometry), vertices'' at the endpoints of the major axis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Engineering Society
The Audio Engineering Society (AES) is a professional body for engineers, scientists, other individuals with an interest or involvement in the professional audio industry. The membership largely comprises engineers developing devices or products for audio, and persons working in audio content production. It also includes acousticians, audiologists, academics, and those in other disciplines related to audio. The AES is the only worldwide professional society devoted exclusively to audio technology. Established in 1948, the Society develops, reviews and publishes engineering standards for the audio and related media industries, and produces the AES Conventions, which are held twice a year alternating between Europe and the US. The AES and individual regional or national ''sections'' also hold ''AES Conferences'' on different topics during the year. History The idea of a society dedicated solely to audio engineering had been discussed for some time before the first meeting, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Range
Spectral bands are regions of a given spectrum, having a specific range of wavelengths or frequencies. Most often, it refers to electromagnetic bands, regions of the electromagnetic spectrum. More generally, spectral bands may also be means in the spectra of other types of signals, e.g., noise spectrum. A frequency band is an interval in the frequency domain, limited by a lower frequency and an upper frequency. For example, it may refer to a '' radio band'', such as wireless communication standards set by the International Telecommunication Union. In nuclear physics In nuclear physics, spectral bands refer to the electromagnetic emission of polyatomic systems, including condensed materials, large molecules, etc. Each ''spectral line'' corresponds to the difference in two energy levels of an atom. In molecules, these levels can split. When the number of atoms is large, one gets a continuum of energy levels, the so-called ''spectral bands''. They are often labeled in the same ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QS Regular Matrix
Quadraphonic Sound (originally called Quadphonic Synthesizer, and later incorrectly referred to as RM or Regular Matrix) was a phase amplitude Matrix decoder, matrix 4-channel quadraphonic sound system for phonograph records. The system was based on technology created by Peter Scheiber, but further developed by engineer Ryosuke Ito of Sansui Electric, Sansui in the early 1970s. The technology was freely licensed and was adopted by many record labels including ABC Records, ABC, Advent, BluesWay Records, BluesWay, Candide, Command Records, Command, Decca Records, Decca, Impulse! Records, Impulse, Longines Symphonette Society, Longines, MCA Records, MCA, Passport Records, Passport, Pye Records, Pye, Turnabout and Vox Records, Vox. More than 600 LP record titles using this technology were released on vinyl during the 1970s. RM (''Regular Matrix'') was often used a synonym for the 'Sansui QS', 'Toshiba QM' and 'Nippon Columbia QX' matrix systems that were previously launched before the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereo Quadraphonic
SQ Quadraphonic ("Stereo Quadraphonic") was a Matrix decoder, matrix 4-channel quadraphonic sound system for Vinyl record, vinyl LP records. It was introduced by Columbia Records, CBS Records (known in the United States and Canada as Columbia Records) in 1971. Many recordings using this technology were released on LP during the 1970s. Record companies who adopted this format include: Angel Records, Angel, CTI Records, CTI, Columbia Records, Columbia (internationally called Columbia Records, CBS Records), EMI, Epic Records, Epic, Eurodisc, Harvest Records, Harvest, His Master's Voice (British record label), His Master's Voice, Seraphim Records, Seraphim, Supraphon and Vanguard Records, Vanguard. With matrix formats, the four sound channels (forward left, forward right, back left, back right) are converted (encoded) down to two channels (left, right). These are then passed through a two-channel transmission medium (usually an LP record) before being decoded back to four channels an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
