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Print-through
Print-through is a generally undesirable effect that arises in the use of magnetic tape for storing analog information, in particular music, caused by contact transfer of signal patterns from one layer of tape to another as it sits wound concentrically on a reel. Explanation Print-through is a category of noise caused by contact transfer of signal patterns from one layer of tape to another after it is wound onto a reel. Print-through can take two forms: # thermo-remanent magnetization induced by temperature, and # anhysteretic magnetization caused by an external magnetic field. The former is unstable over time and can be easily erased by rewinding a tape and letting it sit so that the patterns formed by the contact of upper and lower layers begin to erase each other and form new patterns with the repositioning of upper/lower layers after rewinding. This type of contact printing begins immediately after a recording and increases over time at a rate dependent on the temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Tape
Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic tape can with relative ease record and play back audio, visual, and binary computer data. Magnetic tape revolutionized sound recording and reproduction and broadcasting. It allowed radio, which had always been broadcast live, to be recorded for later or repeated airing. Since the early 1950s, magnetic tape has been used with computers to store large quantities of data and is still used for backup purposes. Magnetic tape begins to degrade after 10–20 years and therefore is not an ideal medium for long-term archival storage. The exception is data tape formats like Linear Tape-Open, LTO which are specifically designed for long-term archiving. Information in magnetic tapes is often recorded in tracks which are narrow and long areas of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Spill
Spill (also known as bleed and leakage) is the occurrence in sound recording (particularly in close miking) and live sound mixing whereby sound is picked up by a microphone from a source other than that which is intended. Spill is usually seen as a problem, and various steps are taken to avoid it or reduce it. In some styles of music, such as orchestral music, jazz, and blues, it is more likely to be accepted or even seen as desirable. Occurrence Spill occurs when sound is detected by a microphone not intended to pick it up (for example, the vocals being detected by the microphone for the guitar). Spill is often undesirable in popular music recording, as the combined signals during the mix process can cause phase cancellation and may cause difficulty in processing individual tracks. It also causes difficulty in overdubbing, where the spill from the sound being replaced may still be audible on other channels. For sound reinforcement in live shows, mic bleed can make it hard fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post-echo
In audio signal processing, pre-echo, sometimes called a '' forward echo'' (not to be confused with reverse echo), is a digital audio compression artifact where a sound is heard before it occurs (hence the name). It is most noticeable in impulsive sounds from percussion instruments such as castanets or cymbals. It occurs in transform-based audio compression algorithms typically based on the modified discrete cosine transform (MDCT) such as MP3, MPEG-4 AAC, and Vorbis, and is due to quantization noise being spread over the entire transform window of the codec. Cause The psychoacoustic component of the effect is that one hears only the echo preceding the transient, not the one following because this latter is drowned out by the transient. Formally, forward temporal masking is much stronger than backwards temporal masking, hence one hears a pre-echo, but no post-echo. Mitigation In an effort to avoid pre-echo artifacts, many sound processing systems use filters where all of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D-2 (video)
D-2 is a professional digital videocassette format created by Ampex and introduced in 1988 at the NAB Show as a composite video alternative to the component video D-1 format. It garnered Ampex a technical Emmy in 1989. Like D-1, D-2 stores uncompressed digital video on a tape cassette; however, it stores a composite video signal, rather than component video as with D-1. While component video is superior for advanced editing, especially when chroma key effects are used, composite video was more compatible with most analog facilities existing at the time. History Ampex created the first D-2 video machine, the ACR-225 commercial spot player working with Sony, who had done some early research into composite digital video, as a cost-effective solution for TV broadcasters with large investments in composite analog infrastructure such as video routers and switchers, since it could be inserted into existing analog broadcast facilities without extensive redesign or modifications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forward Echo
In telecommunications, a forward echo is the propagation of a signal reflection in the same direction as the original signal and consisting of energy reflected back by one discontinuity and then forward again by another discontinuity. Forward echoes can be supported by reflections caused by splices or other discontinuities in the transmission medium (e.g. optical fiber, twisted pair, or coaxial tube). In metallic lines, they may be supported by impedance mismatches between the source or load and the characteristic impedance of the transmission medium. They may cause attenuation distortion. See also * Pre-echo In audio signal processing, pre-echo, sometimes called a '' forward echo'' (not to be confused with reverse echo), is a digital audio compression artifact where a sound is heard before it occurs (hence the name). It is most noticeable in impulsiv ... References Telecommunications engineering Telephony {{telephony-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type C Videotape
1-inch Type C Helical Scan or SMPTE C is a professional reel-to-reel analog recording helical scan videotape format co-developed by Ampex and Sony in 1976. The format uses tape and became the replacement in the professional video and broadcast television industries for the then-incumbent quadruplex videotape open-reel format. Additionally, it replaced the unsuccessful type A format, also developed by Ampex, and primarily in mainland Europe, it supplemented the type B format, developed by the Fernseh division of Bosch. Technical detail Compared to Quad, Type C had a smaller size, comparative ease of operation, and slightly higher video quality. 1-inch Type C is capable of "trick-play" functions such as still, shuttle, and variable-speed playback, including slow motion Slow motion (commonly abbreviated as slow-mo or slo-mo) is an effect in film-making whereby time appears to be slowed down. It was invented by the Austrian priest August Musger in the early 20th century. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type B Videotape
1-inch Type B Helical Scan or SMPTE B is a reel-to-reel analog recording video tape format developed by the Bosch Fernseh division of Bosch in Germany in 1976. The format uses magnetic tape and became the broadcasting standard in continental Europe, but adoption was limited in the United States and United Kingdom, where the Type C videotape format met with greater success. Details The tape speed allowed 96 minutes on a large reel (later 120 minutes), and used 2 record/playback (R/P) heads on the drum rotating at 9,000 RPM with a 190-degree wrap around a very small head drum, recording 52 video lines per head segment. A single video frame or field was recorded across 6 tracks in the tape. The format only allowed for play, rewind and fast forward. Video is recorded on an FM signal with a bandwidth of 5.5 MHz. Three longitudinal audio tracks are recorded on the tape as well: two audio and one Linear timecode (LTC) track. BCN 50 VTRs were used at the 1980 Summer Olympics in M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sine Wave
A sine wave, sinusoidal wave, or sinusoid (symbol: ∿) is a periodic function, periodic wave whose waveform (shape) is the trigonometric function, trigonometric sine, sine function. In mechanics, as a linear motion over time, this is ''simple harmonic motion''; as rotation, it corresponds to ''uniform circular motion''. Sine waves occur often in physics, including wind waves, sound waves, and light waves, such as monochromatic radiation. In engineering, signal processing, and mathematics, Fourier analysis decomposes general functions into a sum of sine waves of various frequencies, relative phases, and magnitudes. When any two sine waves of the same frequency (but arbitrary phase (waves), phase) are linear combination, linearly combined, the result is another sine wave of the same frequency; this property is unique among periodic waves. Conversely, if some phase is chosen as a zero reference, a sine wave of arbitrary phase can be written as the linear combination of two sine wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog
Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog signals **** Analog computer, a computer that uses analog signals ** Analog recording, information recorded using an analog signal * Functional analog (electronic), a system that fulfills the same function as another * Structural analog (electronic), a system that has the same structure as another Entertainment Albums and songs * ''Analog'' (album), an album by Eureka Farm * "Analog" (song), a song by Tyler, The Creator, featuring Hodgy Beats, from ''Goblin'' * ''Analogue'' (album), a 2005 album by A-ha ** "Analogue" (All I Want), the title track of the 2005 album by A-ha Books and magazines * ''Analog Science Fiction and Fact'', a science-fiction magazine * ''ANALOG Computing'', a 1981–1989 magazine about Atari computers * '' A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternating Current
Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, Fan (machine), fans and electric lamps into a wall socket. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', respectively, as when they modify ''Electric current, current'' or ''voltage''. The usual waveform of alternating current in most electric power circuits is a sine wave, whose positive half-period corresponds with positive direction of the current and vice versa (the full period is called a ''wave cycle, cycle''). "Alternating current" most commonly refers to power distribution, but a wide range of other appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
