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Portable Audio Player
A portable audio player is a personal mobile device that allows the user to listen to recorded audio while mobile. Sometimes a distinction is made between a ''portable'' player, battery-powered and with one or more small loudspeakers, and a ''personal'' player, listened to with earphones. History Portable battery-operated reel-to-reel tape recorders were introduced in the 1950s, initially tending to be high-priced units for reporters, produced by Uher and Nagra. Lower-priced units became available later. In the mid-1960s Philips introduced the battery-operated compact cassette recorder, originally used for recording speech. At about the same time the 8-track player was introduced. It was very successful at the time, though bulky and inconvenient to use. There was a pause at the end of each track as the program changed. The compact cassette, although physically much smaller than the 8-track cartridge, became capable of good sound quality as the technology developed, and long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with pronouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant sound, and as (homophone of pronoun ''thee'') when followed by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassette Player
A cassette deck is a type of tape machine for playing and recording audio cassettes that does not have a built-in power amplifier or speakers, and serves primarily as a transport. It can be a part of an automotive entertainment system, a part of a portable mini system or a part of a home component system. In the latter case it is also called a component cassette deck or just a component deck. A "tape recorder" is a more generic term to identify a device that usually has a self-contained power amplifier and either has a built-in speaker or comes packaged with one. History Origins The first consumer tape recorder to employ a tape reel permanently housed in a small removable cartridge was the RCA tape cartridge, which appeared in 1958 as a predecessor to the cassette format. At that time, reel to reel recorders and players were commonly used by enthusiasts, but required large individual reels and tapes which had to be threaded by hand, making them less-accessible to the cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trade-off
A trade-off (or tradeoff) is a situational decision that involves diminishing or losing one quality, quantity, or property of a set or design in return for gains in other aspects. In simple terms, a tradeoff is where one thing increases, and another must decrease. Tradeoffs stem from limitations of many origins, including simple physics – for instance, only a certain volume of objects can fit into a given space, so a full container must remove some items in order to accept any more, and vessels can carry a few large items or multiple small items. Tradeoffs also commonly refer to different configurations of a single item, such as the tuning of strings on a guitar to enable different notes to be played, as well as an allocation of time and attention towards different tasks. The concept of a tradeoff suggests a tactical or strategic choice made with full comprehension of the advantages and disadvantages of each setup. An economic example is the decision to invest in stocks, which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lossy Compression
In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size for storing, handling, and transmitting content. The different versions of the photo of the cat on this page show how higher degrees of approximation create coarser images as more details are removed. This is opposed to lossless data compression (reversible data compression) which does not degrade the data. The amount of data reduction possible using lossy compression is much higher than using lossless techniques. Well-designed lossy compression technology often reduces file sizes significantly before degradation is noticed by the end-user. Even when noticeable by the user, further data reduction may be desirable (e.g., for real-time communication or to reduce transmission times or storage needs). The most widely used lossy compression al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rio PMP300
The Rio PMP300 is one of the first portable consumer MP3 digital audio players, and the first commercially successful one. Produced by Diamond Multimedia, it was introduced September 15, 1998 as the first in the "Rio" series of digital audio players, and it shipped later that year. Features Roughly the dimensions of a deck of cards (3.5 inches by 2.5 inches and 0.625 inches thick), the Rio is black, and features an LCD screen and a circular pad with control buttons. The device has controls for skipping tracks forwards or backwards, repeat, random play and four preset equalizer settings. The LCD displays the track number being played and the track play time. It can play MP2 and MP3 format audio files, and has support for a variety of bitrates, including MP3 variable-bitrate (VBR) support. It shipped with 32 MB of internal memory and has a SmartMedia slot, allowing users to add additional memory. It is powered by a single AA battery, which provides between 8 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hard Disk
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small rectangular box. Introduced by IBM in 1956, HDDs were the dominant secondary storage device for general-purpose computers beginning in the early 1960s. HDDs maintained this position into the modern era of servers and personal computers, though personal computing devices produced in large volume, like cell phones and tablets, rely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Memory
Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both use the same cell design, consisting of floating gate MOSFETs. They differ at the circuit level depending on whether the state of the bit line or word lines is pulled high or low: in NAND flash, the relationship between the bit line and the word lines resembles a NAND gate; in NOR flash, it resembles a NOR gate. Flash memory, a type of floating-gate memory, was invented at Toshiba in 1980 and is based on EEPROM technology. Toshiba began marketing flash memory in 1987. EPROMs had to be erased completely before they could be rewritten. NAND flash memory, however, may be erased, written, and read in blocks (or pages), which generally are much smaller than the entire device. NOR flash memory allows a single machine word to be written to an er ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDRW
CD-RW (Compact Disc-Rewritable) is a digital optical disc storage format introduced in 1997. A CD-RW compact disc (CD-RWs) can be written, read, erased, and re-written. CD-RWs, as opposed to CDs, require specialized readers that have sensitive laser optics. Consequently, CD-RWs cannot be read in many CD readers built prior to the introduction of CD-RW. CD-ROM drives with a "MultiRead" certification are compatible. CD-RWs must be erased or blanked before reuse. Erasure methods include full blanking where the entire surface of the disc is erased and fast blanking where only metadata areas, such as PMA, TOC and pregap, are cleared. Fast blanking is quicker and usually sufficient to allow rewriting the disc. Full blanking removes all traces of the previous data, and is often used for confidentiality purposes. CD-RWs can sustain fewer re-writes compared to other storage media (ca. 1,000 compared up to 100,000). Ideal use is for test discs (e.g. for CD authoring), temporary ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CD-R
CD-R (Compact disc-recordable) is a digital optical disc storage format. A CD-R disc is a compact disc that can be written once and read arbitrarily many times. CD-R discs (CD-Rs) are readable by most CD readers manufactured prior to the introduction of CD-R, unlike CD-RW discs. History Originally named CD Write-Once (WO), the CD-R specification was first published in 1988 by Philips and Sony in the Orange Book, which consists of several parts that provide details of the CD-WO, CD-MO (Magneto-Optic), and later CD-RW (ReWritable). The latest editions have abandoned the use of the term "CD-WO" in favor of "CD-R", while "CD-MO" was rarely used. Written CD-Rs and CD-RWs are, in the aspect of low-level encoding and data format, fully compatible with the audio CD (''Red Book'' CD-DA) and data CD (''Yellow Book'' CD-ROM) standards. The Yellow Book standard for CD-ROM only specifies a high-level data format and refers to the Red Book for all physical format and low-level code ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Headphones
Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earspeakers, earphones or, colloquially, cans. Circumaural ('around the ear') and supra-aural ('over the ear') headphones use a band over the top of the head to hold the speakers in place. Another type, known as earbuds or earpieces consist of individual units that plug into the user's ear canal. A third type are bone conduction headphones, which typically wrap around the back of the head and rest in front of the ear canal, leaving the ear canal open. In the context of telecommunication, a headset is a combination of headphone and microphone. Headphones connect to a signal source such as an au ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereophonic
Stereophonic sound, or more commonly stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configuration of two loudspeakers (or stereo headphones) in such a way as to create the impression of sound heard from various directions, as in natural hearing. Because the multi-dimensional perspective is the crucial aspect, the term ''stereophonic'' also applies to systems with more than two channels or speakers such as quadraphonic and surround sound. Binaural sound systems are also ''stereophonic''. Stereo sound has been in common use since the 1970s in entertainment media such as broadcast radio, recorded music, television, video cameras, cinema, computer audio, and internet. Etymology The word ''stereophonic'' derives from the Greek (''stereós'', "firm, solid") + (''phōnḗ'', "sound, tone, voice") and it was coined in 1927 by Western Ele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sony Walkman
Walkman, stylised as , is a brand of portable audio players manufactured and marketed by Japanese technology company Sony since 1979. The original Walkman was a portable cassette player and its popularity made "walkman" an unofficial term for personal stereos of any producer or brand. By 2010, when production stopped, Sony had built about 200 million cassette-based Walkmans. The Walkman brand was extended to serve most of Sony's portable audio devices, including DAT players, MiniDisc players/recorders, CD players (originally Discman then renamed the CD Walkman), transistor radios, mobile phones, and digital audio/media players. As of 2011, the Walkman range consists exclusively of digital players. Development The Compact Cassette was developed in 1963 by the Dutch electronics firm Philips. In the late 1960s, the introduction of prerecorded compact cassettes made it possible to listen to music on portable devices as well as on car stereos, though gramophone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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