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115-457: Apple PowerCD is a CD player sold by Apple Computer in 1993 and discontinued several years later. It was a re-badged Philips -designed product (Philips CDF-100) which was sold in addition to Apple's speakers and also included a remote control . The PowerCD was capable of reading Kodak photo CDs , data CDs and audio CDs . It can connect to Macintosh personal computers through SCSI and also to stereo systems and televisions . With

230-489: A Betamax video recorder in 1973. After this, in 1974 the leap to storing digital audio on an optical disc was easily made. Sony first publicly demonstrated an optical digital audio disc in September 1976. A year later, in September 1977, Sony showed the press a 30 cm (12 in) disc that could play 60 minutes of digital audio (44,100 Hz sampling rate and 16-bit resolution) using MFM modulation. In September 1978,

345-592: A DJ mixer to transition seamlessly between songs. In the 1970s disco era, DJs typically used two record players . From the 1980s to the 1990s, two compact cassette players became a popular sound source for DJs. In subsequent decades, DJs shifted to CDs and then to digital audio players . DJs who use CDs and CD players typically use specialized DJ CD players that have features not available on regular CD players. DJs who are performing scratching –the creation of rhythmic sounds and sound effects from sound recordings–traditionally used vinyl records and turntables . In

460-611: A headphone jack or RCA jacks . To use a CD player in a home stereo system, the user connects an RCA cable from the RCA jacks to a hi-fi (or other amplifier ) and loudspeakers for listening to music. To listen to music using a CD player with a headphone output jack, the user plugs headphones or earphones into the headphone jack. Modern units can play audio formats other than the original CD PCM audio coding, such as MP3 , AAC and WMA . DJs playing dance music at clubs often use specialized players with an adjustable playback speed to alter

575-428: A photodiode array sensor. The sensor detects changes in the beam, and a digital processing chain interprets these changes as binary data. The data are processed and eventually converted to sound using a digital-to-analog converter (DAC). A TOC or Table of Contents is located after the lead-in area of the disc, which is located in an inner ring of the disc, and contains roughly five kilobytes of available space. It

690-640: A (shallow) groove, a first data layer, a semi-reflective layer, a second (spacer) polycarbonate layer with another (deep) groove, and a second data layer. The first groove spiral usually starts on the inner edge and extends outwards, while the second groove start on the outer edge and extends inwards. Some drives support Hewlett-Packard 's LightScribe , or the alternative LabelFlash photothermal printing technology for labeling specially coated discs. Zen Technology and Sony have developed drives that use several laser beams simultaneously to read discs and write to them at higher speeds than what would be possible with

805-495: A CD player. The boombox CD player is the only type of CD player that produces sound audible by the listener independently, without the need for headphones or an additional amplifier or speaker system. Designed for portability, boomboxes can be powered by batteries as well as by line current. The boombox was introduced to the American market during the mid-1970s. The desire for louder and heavier bass led to bigger and heavier boxes; by

920-578: A Mini CD inserted will refuse to operate until such disc is removed, for example). Non-circular CDs cannot be used on such loaders because they cannot handle non-circular discs. When inserted, such discs may become stuck and damage the mechanism. It is also used on some laptop computers, the original and slim PlayStation 3 , the Wii's original model and its Family Edition and most eighth-generation video game consoles (the Wii U , PlayStation 4 and Xbox One ), as well as

1035-448: A characteristic eye pattern and its usefulness in servicing the machine is paramount for detecting and diagnosing problems, and calibrating CD players for operation. The first stage in the processing chain for the analog RF signal (from the photoreceptor device) is digitizing it. Using various circuits like a simple comparator or a data slicer, the analog signal becomes a chain of two binary digital values, 1 and 0. This signal carries all

1150-415: A computer's USB port . (In some slim drives, two USB connectors are required, each supplying power, but only one the data.) Half height drives are also faster than Slim drives due to this, since more power is required to spin the disc at higher speeds. Half-height optical drives hold discs in place from both sides while slim type optical drives fasten the disc from the bottom. Half height drives fasten

1265-479: A constant number of revolutions per minute (RPM). With CAV, a higher throughput is generally achievable at the outer disc compared to the inner. On the other hand, optical drives were developed with an assumption of achieving a constant throughput, in CD drives initially equal to 150 KiB /s. It was a feature important for streaming audio data that always tend to require a constant bit rate . But to ensure no disc capacity

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1380-420: A constraint on the maximum safe speeds (56× CAV for CDs or around 18×CAV in the case of DVDs) at which drives can operate. The reading speeds of most half-height optical disc drives released since c.  2007 are limited to ×48 for CDs, ×16 for DVDs and ×12 ( angular velocities ) for Blu-ray Discs. Writing speeds on selected write-once media are higher. Some optical drives additionally throttle

1495-439: A diffraction grating is used to split a laser beam into 7 beams, which are then focused into the disc; a central beam is used for focusing and tracking the groove of the disc leaving 6 remaining beams (3 on either side) that are spaced evenly to read 6 separate portions of the groove of the disc in parallel, effectively increasing read speeds at lower RPMs, reducing drive noise and stress on the disc. The beams then reflect back from

1610-447: A lower reading speed improves readability of damaged media. With an option in the optical disc authoring software, optical disc writers are able to simulate the writing process on CD-R , CD-RW , DVD-R and DVD-RW , which allows for testing such as observing the writing speeds and patterns (e.g. constant angular velocity , constant linear velocity and P-CAV and Z-CLV variants) with different writing speed settings and testing

1725-422: A magnetic actuator mounted on a swing-arm to do coarse and fine tracking. Using only one laser beam and the 4 photodiode block, the servo knows if the track is centered by measuring side-by-side movement of the light of beam hitting on the block and corrects to keep the light on the center. The other design by Sony uses a diffraction grating to part the laser light into one main beam and two sub-beams. When focused,

1840-471: A mechanism that scans the circular data tracks using a laser beam. An electric motor spins the disc. The tracking control is done by analog servo amplifiers and then the high-frequency analog signal read from the disc is digitized, processed and decoded into analog audio and digital control data which is used by the player to position the playback mechanism on the correct track, do the skip and seek functions and display track, time, index and, on newer players in

1955-500: A million copies on CD was Dire Straits , with their 1985 album Brothers in Arms . The first major artist to have his entire catalogue converted to CD was David Bowie , whose 15 studio albums were made available by RCA Records in February 1985, along with four greatest hits albums. In 1988, 400 million CDs were manufactured by 50 pressing plants around the world. The CD was planned to be

2070-455: A modification. A picture of this early design can be seen on the Panasonic Web site. The vertical loading is similar the one common in cassette decks , where the holder opens, and disc is dropped to it. The holder is closed manually, by motor after pressing a button, or completely automatically. Some CD players combine vertical loading with slot loading due to the disc being drawn further into

2185-477: A motorized mechanism that can be pushed to close, controlled by the computer, or controlled using a button on the drive. Trays on half height and slim drives can also be locked by whatever program is using it, however it can still be ejected by inserting the end of a paper clip into an emergency eject hole on the front of the drive. Early CD players such as the Sony CDP-101 used a separate motorized mechanism to clamp

2300-406: A motorized tray (as utilized by half-height , "desktop" drives), a manually operated tray (as utilized in laptop computers, also called slim type ), or a slot-loading mechanism, where the disc is slid into a slot and drawn in by motorized rollers. Slot-loading optical drives exist in both half-height (desktop) and slim type (laptop) form factors. With both types of mechanisms, if a CD or DVD

2415-519: A pair of headphones . The first portable CD player released was the D-50 by Sony . The D-50 was made available on the market in 1984, and adopted for Sony's entire portable CD player line. In 1998, portable MP3 players began to compete with portable CD players. After Apple Computer entered the music player market with its iPod line, within ten years it became the dominant seller of portable digital audio players, "...while former giant Sony (maker of

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2530-405: A partial CLV (PCLV) scheme, by switching from CLV to CAV only when a rotational limit is reached. But switching to CAV requires considerable changes in hardware design, so instead most drives use the zoned constant linear velocity (Z-CLV) scheme. This divides the disc into several zones, each having its own constant linear velocity. A Z-CLV recorder rated at "52×", for example, would write at 20× on

2645-412: A point on the media, thus its power has to increase proportionally. DVD burners' lasers often peak at about 200 mW, either in continuous wave and pulses, although some have been driven up to 400 mW before the diode fails. For rewritable CD-RW , DVD-RW , DVD+RW , DVD-RAM , or BD-RE media, the laser is used to melt a crystalline metal alloy in the recording layer of the disc. Depending on

2760-466: A result, in 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. Led by engineers Kees Schouhamer Immink and Toshitada Doi , the research pushed forward laser and optical disc technology. After a year of experimentation and discussion, the task force produced the Red Book CD-DA standard. First published in 1980, the standard was formally adopted by

2875-408: A semi-reflective layer. Both layers are accessible from the same side, but require the optics to change the laser's focus. Traditional single layer (SL) writable media are produced with a spiral groove molded in the protective polycarbonate layer (not in the data recording layer), to lead and synchronize the speed of recording head. Double-layered writable media have: a first polycarbonate layer with

2990-458: A single laser beam. The limitation with a single laser beam comes from wobbling of the disc that may occur at high rotational speeds; at 25,000 RPMs CDs become unreadable while Blu-rays cannot be written to beyond 5,000 RPMs. With a single laser beam, the only way to increase read and write speeds without reducing the pit length of the disc (which would allow for more pits and thus bits of data per revolution, but may require smaller wavelength light)

3105-453: A standard DVD holds 4.7  gigabytes , however, higher-capacity formats such as multi-layer Blu-ray Discs exist) for local use, and data for distribution, but only on a small scale; mass-producing large numbers of identical discs by pressing (replication) is cheaper and faster than individual recording (duplication). To support 8 centimetre diameter discs, drives with mechanical tray loading (desktop computer drives) have an indentation in

3220-415: A stop. The most important part of an optical disc drive is an optical path , which is inside a pickup head ( PUH ). The PUH is also known as a laser pickup, optical pickup, pickup, pickup assembly, laser assembly, laser optical assembly, optical pickup head/unit or optical assembly. It usually consists of a semiconductor laser diode , a lens for focusing the laser beam, and photodiodes for detecting

3335-642: A team." Red Book was the first standard in the Rainbow Books series of standards. Philips established the Polydor Pressing Operations plant in Langenhagen near Hannover , Germany , and quickly passed a series of milestones. The Japanese launch was followed in March 1983 by the introduction of CD players and discs to Europe and North America (where CBS Records released sixteen titles). This event

3450-700: A third one for Blu-ray Discs if supported by the drive ) that can be turned using a fine screwdriver. The potentiometer is in a series circuit with the laser lens. The laser diode used in DVD writers can have powers of up to 100 milliwatts , such high powers are used during writing. Some CD players have automatic gain control (AGC) to vary the power of the laser to ensure reliable playback of CD-RW discs. Readability (the ability to read physically damaged or soiled discs) may vary among optical drives due to differences in optical pickup systems, firmwares, and damage patterns. On factory-pressed read only media (ROM), during

3565-504: A year later. The original speakers came in Platinum gray to match Apple's desktop line, while the second generation were curvier and also came in a darker gray color designed to match the PowerBook line and PowerCD. Both were powered with an AC adapter and could be attached to any audio output source, with two separate inputs for the computer and an external CD player. Both had a headphone jack in

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3680-545: A year of experimentation and discussion, the Red Book CD-DA standard was published in 1980. After their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $ 1,000, over 400,000 CD players were sold in the United States between 1983 and 1984. The success of the compact disc has been credited to the cooperation between Philips and Sony , who came together to agree upon and develop compatible hardware. The unified design of

3795-429: Is 1.385 MB/s, equal to 1.32 MiB/s, approximately nine times faster than the CD base speed. For Blu-ray drives, base speed is 6.74 MB/s, equal to 6.43 MiB/s. Because keeping a constant transfer rate for the whole disc is not so important in most contemporary CD uses, a pure CLV approach had to be abandoned to keep the rotational speed of the disc safely low while maximizing data rate. Some drives work in

3910-490: Is a DVD player/boombox with a top-loading CD/ DVD drive and an LCD video screen in the position once occupied by a cassette deck. Many models of this type of boombox include inputs for external video (such as television broadcasts) and outputs to connect the DVD player to a full-sized television. Disc jockeys (DJs) who are playing a mix of songs at a dance club , rave , or nightclub create their dance mixes by having songs playing on two or more sound sources and using

4025-450: Is by increasing the rotational speed of the disc which reads more pits in less time, increasing data rate; hence why faster drives spin the disc at higher speeds. In addition, CDs at 27,500 RPMs (such as to read the inside of a CD at 52x) may explode causing extensive damage to the disc's surroundings, and poor quality or damaged discs may explode at lower speeds. In Zen's system (developed in conjunction with Sanyo and licensed by Kenwood),

4140-453: Is fed to two systems, one integrated in the focus lens assembly can do fine tracking correction and the other system can move the entire optical assembly side by side to do coarse track jumps. The sum of the output from the four photodiodes makes the RF or high-frequency signal which is an electronic mirror of the pits and lands recorded on the disc. The RF signal, when observed on an oscilloscope, has

4255-409: Is in charge of keeping focused the beam on the 600  nm wide data track. When the player tries to read from a stop, it first does a focus seek program that moves the lens up and down from the surface of the disc until a reflection is detected; when there is a reflection, the servo electronics lock in place keeping the lens in perfect focus while the disc rotates and changes its relative height from

4370-404: Is invalid, erroneous or missing audio data, it cannot be output to the speakers as digital noise, it has to be muted. The Audio CD format requires every player to have enough processing power to decode the CD data; this is normally made by application-specific integrated circuits (ASICs). ASICs do not work by themselves, however; they require a main microcomputer or microcontroller to orchestrate

4485-456: Is left in the drive after the computer is turned off, the disc cannot be ejected using the normal eject mechanism of the drive. However, tray-loading drives account for this situation by providing a small hole where one can insert a paperclip to manually open the drive tray to retrieve the disc. Slot-loading optical disc drives are prominently used in game consoles and vehicle audio units. Although allowing more convenient insertion, those have

4600-414: Is less practical. Large backups are often instead made on external hard drives, as their price has dropped to a level making this viable; in professional environments magnetic tape drives are also used. Some optical drives also allow predictively scanning the surface of discs for errors and detecting poor recording quality. The drive reduces the rotation speed of discs when encountering damage, since

4715-401: Is not based on Russell's invention; it is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s. In 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. After

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4830-450: Is often seen as the "Big Bang" of the digital audio revolution. The new audio disc was enthusiastically received, especially in the early-adopting classical music and audiophile communities, and its handling quality received particular praise. As the price of players gradually came down, and with the introduction of the portable Walkman , the CD began to gain popularity in the larger popular and rock music markets. The first artist to sell

4945-414: Is the first information that the player reads when the disc is loaded in the player and contains information on the total number of audio tracks, the running time on the CD, the running time of each track, and other information such as ISRC and the format structure of the disc. The TOC is of such vital importance for the disc that if it is not read correctly by the player, the CD could not be played back. That

5060-439: Is the preferred loading mechanism for car audio players. There is no tray that pops out, and a motor is used to assist disc insertion and removal. Some slot-loading mechanisms and changers can load and play back Mini-CDs without the need of an adapter (such as the original Wii model's standard-sized disc slot being capable of accepting smaller GameCube Game Discs ) but they may work with limited functionality (a disc changer with

5175-597: Is why it is repeated three times before the first music program starts. The lead out area in the end (the outer peripheral) of the disc tells the player that disc has come to an end. CD players can employ a number of ways to improve performance or reduce component count or price. Features such as oversampling, one-bit DACs, dual DACs, interpolation (error correction), anti-skip buffering, digital and optical outputs are, or were, likely to be found. Other features improve functionality, such as track programming, random play and repeat, or direct track access. Yet others are related to

5290-574: The IEC as an international standard in 1987, with various amendments becoming part of the standard in 1996. Philips coined the term compact disc in line with another audio product, the Compact Cassette , and contributed the general manufacturing process , based on video LaserDisc technology. Philips also contributed eight-to-fourteen modulation (EFM), which offers a certain resilience to defects such as scratches and fingerprints, while Sony contributed

5405-821: The PlayStation and Xbox consoles are the only home video game consoles that are currently using optical discs as its primary storage format, as the Wii U 's successor, the Nintendo Switch , began using game cartridges , while the PlayStation Portable is the only handheld console to use optical discs, using Sony's proprietary UMD format. They are also very commonly used in computers to read software and media distributed on disc and to record discs for archival and data exchange purposes. Floppy disk drives , with capacity of 1.44 MB, have been made obsolete: optical media are cheap and have vastly higher capacity to handle

5520-529: The TSST TS-LB23, which can only read Blu-ray discs but read and write CDs and DVDs. As of 2021 , most of the optical disc drives on the market are DVD and Blu-ray drives which read from and record to those formats, along with having backward compatibility with audio CD , CD-R / -RW , and CD-ROM discs. Compact disc drives are no longer manufactured outside of audio devices. Read-only DVD and Blu-ray drives are also manufactured, but are less commonly found in

5635-427: The error-correction method, CIRC . The Compact Disc Story , told by a former member of the task force, gives background information on the many technical decisions made, including the choice of the sampling frequency, playing time, and disc diameter. The task force consisted of around four to eight persons, though according to Philips, the compact disc was "invented collectively by a large group of people working as

5750-404: The ninth-generation PlayStation 5 and Xbox Series X . Two types of optical tracking mechanisms exist: The swing-arm mechanism has a distinctive advantage over the other in that it does not skip when the rail becomes dirty. The swing arm mechanisms tend to have a much longer life than their radial counterparts. The main difference between the two mechanisms is the way they read the data from

5865-412: The pitch and tempo of the music. Audio engineers using CD players to play music for an event through a sound reinforcement system use professional audio-grade CD players. CD playback functionality is also available on CD-ROM/DVD-ROM drive equipped computers as well as on DVD players and most optical disc-based home video game consoles . American inventor James T. Russell is known for inventing

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5980-513: The 1980s, some boomboxes had reached the size of a suitcase . Most boomboxes were battery-operated, leading to extremely heavy, bulky boxes. Most boomboxes from the 2010s typically include a CD player compatible with CD-R and CD-RW , which allows the user to carry their own music compilations on a higher fidelity medium. Many also permit iPod and similar devices to be plugged into them through one or more auxiliary input jacks. Some also support formats such as MP3 and WMA . Another modern variant

6095-411: The 2010s, display title and artist information on a display placed in the front panel. To read the data from the disc, a laser beam shines on the surface of the disc. Surface differences between discs being played, and tiny position differences once loaded, are handled by using a movable lens with a very close focal length to focus the light on the disc. A low-mass lens coupled to an electromagnetic coil

6210-605: The 2010s, some specialized DJ CD players can be used to create the same scratching effects using songs on CDs. Optical disc drive Although most laptop manufacturers no longer have optical drives bundled with their products, external drives are still available for purchase separately. Some drives can only read data where as others can both read data and write data to writable discs. Drives which can read but not write data are "-ROM" (read-only memory) drives, even if they can read from writable formats such as "-R" and "-RW". Some drives have mixed read and write capabilities, such as

6325-413: The CD player's intended target, such as anti-skip for car and portable CD players, pitch control and queuing for a DJ's CD player, remote and system integration for household players. Description of some features follows: A portable CD player is a portable audio player used to play compact discs . Portable CD players are powered by batteries and they have a 1/8" headphone jack into which the user plugs

6440-561: The Philips CD100 chassis. Top-loading was adopted on various equipment designs such as mini systems and portable CD players, but among stereo component CD players, only a handful of top-loading models have been made. Examples include Luxman 's D-500 and D-500X series players and Denon 's DP-S1, both launched in 1993. Top-loading is also common in players intended for broadcast and live sound DJ use, such as Technics' SL-P50 (1984–1985) and Technics SL-P1200 (1986–1992). They more closely mimic

6555-568: The Sony prototype design was never put into volume production, the concept was for a time adopted for production by a number of early Japanese CD player manufacturers, including Alpine/Luxman , Matsushita under the Technics brand, Kenwood and Toshiba/Aurex . For the early vertical loading players, Alpine sourced their AD-7100 player designs for Luxman, Kenwood and Toshiba (using their Aurex brand). Kenwood added their Sigma Drive outputs to this design as

6670-426: The United States. In Japan, however, over 80 percent of music was bought on CDs and other physical formats as of 2015. As of 2020, compact cassettes, vinyl records, and CDs are still being released by some musicians, primarily as merchandise, to allow fans to provide financial support while receiving something tangible in return. The process of playing an audio CD, touted as a digital audio storage medium, starts with

6785-549: The [portable] Walkman and [CD] Discman [was] struggling." This market shift was initiated when the first portable digital audio player, the Rio digital music player , was introduced. The 64 MB Rio MP3 player enabled users to store about 20 songs. One of the benefits of the Rio over portable CD players was that since the Rio had no moving parts, it offered skip-free playback. Since 1998, the price of portable digital audio players has dropped and

6900-549: The added ability to be marketed as a stand-alone portable CD player. However, Mac Like Things was short-lived and by September 1992, it was folded into Apple's New Media Group having only brought to market the PowerCD and AppleDesign Powered Speakers series. Along with the PowerCD, Apple released two versions of their desktop speakers: the AppleDesign Powered Speakers and the redesigned AppleDesign Powered Speakers II

7015-543: The advent and popularity of Internet-based distribution of files in lossily-compressed audio formats such as MP3 , sales of CDs began to decline in the 2000s. For example, between 2000 and 2008, despite overall growth in music sales and one anomalous year of increase, major-label CD sales declined overall by 20% – although independent and DIY music sales may be tracking better (according to figures released 30 March 2009), and CDs still continue to sell greatly. As of 2012, CDs and DVDs made up only 34 percent of music sales in

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7130-461: The amount of power applied, the substance may be allowed to melt back (change the phase back) into crystalline form or left in an amorphous form, enabling marks of varying reflectivity to be created. Double-sided media may be used, but they are not easily accessed with a standard drive, as they must be physically turned over to access the data on the other side. Double layer or dual layer (DL) media have two independent data layers separated by

7245-408: The audio division of Philips , started a small group with the aim to develop an analog optical audio disc with a diameter of 20 cm (7.9 in) and a sound quality superior to that of the vinyl record. However, due to the unsatisfactory performance of the analog format, two Philips research engineers recommended a digital format in March 1974. In 1977, Philips then established a laboratory with

7360-504: The compact disc allowed consumers to purchase any disc or player from any company, and allowed the CD to dominate the at-home music market unchallenged. The Sony CDP-101 , released in 1982, was the world's first commercially released compact disc player. It was originally sold only in Japan. Unlike early LaserDisc players, first CD players already used laser diodes instead of larger helium-neon lasers . In 1974, Lou Ottens, director of

7475-502: The company demonstrated an optical digital audio disc with a 150-minute playing time, 44,056 Hz sampling rate, 16-bit linear resolution, and cross-interleaved error correction code—specifications similar to those later settled upon for the standard compact disc format in 1980. Technical details of Sony's digital audio disc were presented during the 62nd AES Convention, held on 13–16 March 1979, in Brussels . Sony's AES technical paper

7590-596: The consumer market and mainly limited to media devices such as game consoles and disc media players. Laptop computers used to come with built-in optical drives. Some laptop computers used modular systems (see Lenovo UltraBay). Throughout the 2010s, they ceased to come with built-in optical disc drives in order to reduce costs and make them lighter, requiring consumers to purchase external optical drives. Optical disc drives are an integral part of standalone appliances such as CD players , DVD players , Blu-ray Disc players, DVD recorders , and video game consoles. As of 2017,

7705-454: The correction is made by interpolating the data from subsequent frames so the missing part is not noticed. Each player has a different interpolation ability. If too many data frames are missing or unrecoverable, the audio signal may be impossible to fix by interpolation, so an audio mute flag is raised to mute the DAC to avoid invalid data to be played back. The Redbook standard dictates that, if there

7820-578: The disadvantages that they cannot usually accept the smaller 80 mm diameter discs (unless 80 mm optical disc adapter is used) or any non-standard sizes, usually have no emergency eject hole or eject button, and therefore have to be disassembled if the optical disc cannot be ejected normally. However, some slot-loading optical drives have been engineered to support miniature discs. The Nintendo Wii , because of backward compatibility with GameCube games, and PlayStation 3 video game consoles are able to load both standard size DVDs and 80 mm discs in

7935-507: The disc holder as it closes. In 1983, Philips , at the US and European launch of the CD format, showcased the first top loading CD tray designs with their CD100 CD player. (Philips audio products were sold as Magnavox in the US at the time.) The design had a clamp on the lid which meant the user had to close this over the CD when it was placed inside the machine. Later, Meridian introduced their MCD high end CD player, with Meridian electronics in

8050-405: The disc to the motorized spindle. Slim drives use a special spindle with spring loaded specially shaped studs that radiate outwards, pressing against the inner edge of the disc. The user has to put uniform pressure onto the inner circumference of the disc to clamp it to the spindle and pull from the outer circumference while placing the thumb on the spindle to remove the disc, flexing it slightly in

8165-412: The disc using 2 spindles containing a magnet each, one under and one above the disc tray. The spindles may be lined with flocking or a texturized silicone material to exert friction on the disc, to keep it from slipping. The upper spindle is left slightly loose and is attracted to the lower spindle because of the magnets they have. When the tray is opened, a mechanism driven by the movement of the tray pulls

8280-410: The disc, and are collimated and projected into a special photodiode array to be read. The first drives using the technology could read at 40x, later increasing to 52x and finally 72x. It uses a single optical pickup. In Sony's system (used on their proprietary Optical Disc Archive system which is based on Archival Disc , itself based on Blu-ray) the drive has 4 optical pickups, two on each side of

8395-412: The disc, with each pickup having two lenses for a total of 8 lenses and laser beams. This allows for both sides of the disc to be read and written to at the same time, and for the contents of the disc to be verified during writing. The rotational mechanism in an optical drive differs considerably from that of a hard disk drive's, in that the latter keeps a constant angular velocity (CAV), in other words

8510-432: The disc. The swing-arm mechanism uses a magnetic coil wound over a permanent magnet to provide the tracking movement to the laser assembly in a similar way a hard drive moves its head across the data tracks. It also uses another magnetic movement mechanism attached to the focusing lens to focus the laser beam on the disc surface. By operating the tracking or the focus actuators, the laser beam can be positioned on any part of

8625-402: The disc. This mechanism employs a single laser beam and a set of four photodiodes to read, focus and keep track of the data coming from the disc. The linear tracking mechanism uses a motor and reduction gears to move the laser assembly radially across the tracks of the disc and it also has a set of six coils mounted in the focusing lens over a permanent magnetic field. One set of two coils moves

8740-410: The dye, thereby creating marks that can be read like the pits and lands on pressed discs. For recordable discs, the process is permanent and the media can be written to only once. While the reading laser is usually not stronger than 5 mW , the writing laser is considerably more powerful. DVD lasers operate at voltages of around 2.5 volts. The higher the writing speed, the less time a laser has to heat

8855-600: The early 2000s, the CD player had largely replaced the audio cassette player as standard equipment in new automobiles, with 2010 being the final model year for any car in the US to have a factory-equipped cassette player. Currently, with the increasing popularity of portable digital audio players, such as mobile phones, and solid state music storage, CD players are being phased out of automobiles in favor of minijack auxiliary inputs and connections to USB devices. Some CD players incorporate disc changers. Commonly these can hold 3, 5, 6, or 10 discs at once and change from one disc to

8970-403: The entire machine. The firmware of basic CD players typically is a real-time operating system . Some early optical computer drives are equipped with an audio connector and buttons for standalone CD playback functionality. Sony released its CDP-101 CD player in 1982 with a slide-out tray design for the CD. As it was easy to manufacture and to use, most CD player manufacturers stayed with

9085-405: The first system to record digital video information on an optical transparent foil that is lit from behind by a high-power halogen lamp. Russell's patent application was first filed in 1966, and he was granted a patent in 1970. Following litigation, Sony and Philips licensed Russell's recording patents (then held by a Canadian company, Optical Recording Corp.) in the 1980s. The compact disc

9200-585: The front of one speaker along with the volume control and an optional subwoofer connection port on some models. CD player A CD player is an electronic device that plays audio compact discs , which are a digital optical disc data storage format. CD players were first sold to consumers in 1982. CDs typically contain recordings of audio material such as music or audiobooks . CD players may be part of home stereo systems, car audio systems, personal computers , or portable CD players such as CD boomboxes . Most CD players produce an output signal via

9315-792: The highest capacity of an individual disc that would be achievable using overburning , without writing any data to the disc. Few optical drives allow simulating a FAT32 flash drive from optical discs containing ISO9660 / Joliet and UDF file systems or audio tracks (simulated as .wav files ), for compatibility with most USB multimedia appliances. Optical drives for computers come in two main form factors: half-height (also known as desktop drive ) and slim type (used in laptop computers and compact desktop computers ). They exist as both internal and external variants. Half-height optical drives are around 4 centimetres tall, while slim type optical drives are around 1 cm tall. Half-height optical drives operate upwards of twice

9430-502: The information in a CD and is modulated using a system called EFM (Eight-to-fourteen modulation). The second stage is demodulating the EFM signal into a data frame that contains the audio samples, error correction parity bits, according with the CIRC error correction code, and control data for the player display and micro-computer. The EFM demodulator also decodes part of the CD signal and routes it to

9545-479: The innermost zone and then progressively increase the speed in several discrete steps up to 52× at the outer rim. Without higher rotational speeds, increased read performance may be attainable by simultaneously reading more than one point of a data groove, also known as multi-beam , but drives with such mechanisms are more expensive, less compatible, and very uncommon. Both DVDs and CDs have been known to explode when damaged or spun at excessive speeds . This imposes

9660-406: The large files used since the days of floppy disks, and the vast majority of computers and much consumer entertainment hardware have optical writers. USB flash drives , high-capacity, small, and inexpensive, are suitable where read/write capability is required. Disc recording is restricted to storing files playable on consumer appliances ( films , music, etc.), relatively small volumes of data (e.g.

9775-422: The laser beam is focused as a small laser spot on the disc. The second servo moves the pickup head along the disc's radius, keeping the beam on the track , a continuous spiral data path. Optical disc media are 'read' beginning at the inner radius to the outer edge. Near the laser lens, optical drives are usually equipped with one to three tiny potentiometers (usually separate ones for CDs , DVDs , and usually

9890-417: The lens closer to the disc surface, providing the focusing motion, and the other set of coils moves the lens radially, providing a finer tracking motion. This mechanism uses the three-beam tracking method in which a main laser beam is used to read and focus the data track of the disc using three or four photodiodes, depending on the focus method, and two smaller beams read the adjacent tracks at each side to help

10005-402: The light reflected from the disc's surface. Initially, CD-type lasers with a wavelength of 780 nm (within the infrared) were used. For DVDs, the wavelength was reduced to 650 nm (red color), and for Blu-ray Disc this was reduced even further to 405 nm (violet color). Two main servomechanisms are used, the first to maintain the proper distance between lens and disc, to ensure

10120-416: The lower spindle away from the upper spindle and vice versa when the tray is closed. When the tray is closed, the lower spindle touches the inner circumference of the disc, and slightly raises the disc from the tray to the upper spindle, which is attracted to the magnet on the lower disc, clamping the disc in place. Only the lower spindle is motorized. Trays in half height drives often fully open and close using

10235-464: The manufacturing process the tracks are formed by pressing a thermoplastic resin into a nickel stamper that was made by plating a glass 'master' with raised 'bumps' on a flat surface, thus creating pits and lands in the plastic disk. Because the depth of the pits is approximately one-quarter to one-sixth of the laser's wavelength, the reflected beam's phase is shifted in relation to the incoming beam, causing mutual destructive interference and reducing

10350-440: The mission of creating a digital audio disc. The diameter of Philips's prototype compact disc was set at 11.5 cm (4.5 in), the diagonal of an audio cassette. Heitaro Nakajima , who developed an early digital audio recorder within Japan's national public broadcasting organization NHK in 1970, became general manager of Sony 's audio department in 1971. His team developed a digital PCM adaptor audio tape recorder using

10465-402: The next without user intervention. Disc changers capable of holding up to 400 discs at once were available. Also, the user can manually choose the disc to be played, making it similar to a jukebox . They were often built into car audio and home stereo systems, although 7 disc CD changers were once made by NEC and Nakamichi for PCs. Some could also play DVD and Blu-ray discs. Meanwhile, with

10580-425: The optical block. Different brands and models of optical assemblies use different methods of focus detection. On most players, the focus position detection is made using the difference in the current output of a block of four photodiodes. The photodiode block and the optics are arranged in such a way that a perfect focus projects a circular pattern on the block while a far or near focus projects an ellipse differing in

10695-454: The outer rim and 500 RPM on the inner, keeping the data rate constant. Later CD drives kept the CLV paradigm, but evolved to achieve higher rotational speeds, popularly described in multiples of a base speed. As a result, a 4× CLV drive, for instance, would rotate at 800-2000 RPM, while transferring data steadily at 600 KiB/s, which is equal to 4 × 150 KiB/s. For DVDs, base or 1× speed

10810-409: The outside edge. (A disc played from beginning to end slows its rotation rate during playback.) The tracking mechanism moves the lens system along the spiral tracks in which information is encoded, and the lens assembly reads the information using a laser beam produced by a laser diode . The laser reads information by focusing a beam on the CD, which is reflected off the disc's mirrored surface back to

10925-473: The physical arrangement and ergonomics of record turntables used in those applications. The top-loading disc tray design is also used in most fifth-generation video game consoles ( PlayStation , Saturn , 3DO Interactive Multiplayer ), as well as the Dreamcast , GameCube , and Wii Mini . The Philips CD303 of 1983-1984 was the first player to adopt tray loading with a sliding play mechanism. Basically, as

11040-408: The plastic polycarbonate compact disc, a medium that contains the digitally encoded data. The disc is placed in a tray that either opens up (as with portable CD players) or slides out (the norm with in-home CD players, computer disc drives and game consoles). In some systems, the user slides the disc into a slot (e.g., car stereo CD players). Once the disc is loaded into the tray, the data is read out by

11155-423: The position of the long edge in north–south or west-southwest. That difference is the information that the servo amplifier uses to keep the lens at the proper reading distance during the playback operation, even if the disc is warped. Another servo mechanism in the player is in charge of keeping the focused beam centered on the data track. Two optical pick-up designs exist, the original CDM series from Philips use

11270-407: The process and returning to its normal shape after removal. The outer rim of the spindle may have a texturized silicone surface to exert friction keeping the disc from slipping. In slim drives most if not all components are on the disc tray, which pops out using a spring mechanism that can be controlled by the computer. These trays cannot close on their own; they have to be pushed until the tray reaches

11385-430: The proper circuits, separating audio, parity and control (subcode) data. After demodulating, a CIRC error corrector takes each audio data frame, stores it in a SRAM memory and verifies that it has been read correctly, if it is not, it takes the parity and correction bits and fixes the data, then it moves it out to a DAC to be converted to an analog audio signal. If the data missing is enough to make recovery impossible,

11500-475: The reading speed based on the contents of optical discs, such as max. 40× CAV (constant angular velocity) for the Digital Audio Extraction ( “DAE” ) of Audio CD tracks, 16× CAV for Video CD contents and even lower limitations on earlier models such as 4× CLV ( constant linear velocity ) for Video CDs . Current optical drives use either a tray-loading mechanism, where the disc is loaded onto

11615-409: The reflected beam's intensity. This is detected by photodiodes that create corresponding electrical signals. An optical disk recorder encodes (also known as burning, since the dye layer is permanently burned) data onto a recordable CD-R , DVD-R , DVD+R , or BD-R disc (called a blank ) by selectively heating (burning) parts of an organic dye layer with a laser. This changes the reflectivity of

11730-438: The same slot-loading drive. Its successor's slot drive however, the Wii U , lacks miniature disc compatibility. There were also some early CD-ROM drives for desktop PCs in which its tray-loading mechanism will eject slightly and user has to pull out the tray manually to load a CD , similar to the tray ejecting method used in internal optical disc drives of modern laptops and modern external slim portable optical disc drives. Like

11845-416: The servo keep the tracking using two more helper photodiodes . A CD player has three major mechanical components: a drive motor , a lens system or pickup head, and a tracking mechanism . The drive motor (also called spindle) spins the disc to a scanning velocity of 1.2–1.4 m/s ( constant linear velocity ) – equivalent to approximately 500 RPM at the inside of the disc, and approximately 200 RPM at

11960-544: The speeds as slim type optical drives, because speeds on slim type optical drives are constrained to the physical limitations of the drive motor's rotation speed (around 5000 rpm ) rather than the performance of the optical pickup system . Because half-height demand much more electrical power and a voltage of 12 V DC, while slim optical drives run on 5 volts, external half height optical drives require separate external power input, while external slim type are usually able to operate entirely on power delivered through

12075-435: The storage capacity has increased significantly. In the 2000s, users can "carry [their] entire music collection in a [digital audio] player the size of a cigarette package." The 4 GB iPod, for example, holds over 1,000 songs. A boombox is a common term for a portable cassette and AM/FM radio that consists of an amplifier, two or more loudspeakers and a carrying handle. Beginning in the 1990s, boomboxes typically included

12190-470: The success of the Apple Newton , in mid-1992 Apple Industrial Design Group created a division called Mac Like Things which was to focus on what they saw as a whole new market for Apple in consumer electronic devices. The PowerCD marked Apple's first stand-alone consumer-oriented product brought to market, which did not require a computer for use. It was analogous to Sony 's Discman portable CD players of

12305-424: The successor of the gramophone record for playing music, rather than primarily as a data storage medium, but from its origins as a format for music, its use has grown to encompass other applications. In 1983, following the CD's introduction, Immink and Braat presented the first experiments with erasable compact discs during the 73rd AES Convention. In June 1985, the computer-readable CD-ROM (read-only memory)

12420-509: The time, however, unlike Sony's and most others, Apple's could also be used as computer peripheral as well. And while most desktop Macs at the time included built-in CD-ROMs, the PowerCD was designed to match the PowerBook series which would not include a built-in CD-ROM for several more years. Its ability to be operated under battery power alone made it not only a portable drive for computers, but gave it

12535-488: The tray came out to collect the CD, the entire player's transport system also came out as one unit. The Meridians 200 and 203 players were of this type. They were also the first to use a design in which the audio electronics were in a separate enclosure from the CD drive and pickup mechanism. A similar mechanism is used in slim optical disc drives (also known as slim internal DVD drive, optical drive or DVD burner), which were once commonly used in laptop computers. Slot loading

12650-533: The tray style ever since. The tray mechanism is also used in many modern desktop computer cases , as well as the Philips CD-i , PlayStation 2 , Xbox and Xbox 360 . However, there have been some notable exceptions to this common CD tray design. During the launch of the first prototype Goronta CD player by Sony at the Japanese Audio Fair in 1982, Sony showcased the vertical loading design. Although

12765-412: The tray. It can however only be used in horizontal operation. Slot loading drives, frequently used in game consoles and car radios, might be able to accept 8 centimetre discs and center the disc automatically. Optical discs are used to back up relatively small volumes of data, but backing up of entire hard drives, which as of 2015 typically contain many hundreds of gigabytes or even multiple terabytes,

12880-428: The two peripheral beams cover the border of the adjacent tracks a few micrometers apart from the main beam and reflect back on two photodiodes separated from the main block of four. The servo detects the RF signal being received on the peripheral receivers and the difference in output between these two diodes conform the tracking error signal that the system uses to keep the optics in the proper track. The tracking signal

12995-501: Was introduced and, in 1990, the CD-Recordable , also developed by both Sony and Philips. Recordable CDs were a new alternative to tape for recording music and copying music albums without the defects introduced in the compression used in other digital recording methods. Other newer video formats such as DVD and Blu-ray use the same physical geometry as CD, and most DVD and Blu-ray players are backward compatible with audio CD. By

13110-481: Was published on 1 March 1979. A week later, on 8 March, Philips publicly demonstrated a prototype of an optical digital audio disc at a press conference called "Philips Introduce Compact Disc" in Eindhoven , Netherlands . Sony executive Norio Ohga , later CEO and chairman of Sony, and Heitaro Nakajima were convinced of the format's commercial potential and pushed further development despite widespread skepticism. As

13225-483: Was wasted, a head had to transfer data at a maximum linear rate at all times too, without slowing on the outer rim of the disc. This led to optical drives—until recently—operating with a constant linear velocity (CLV). The spiral groove of the disc passed under its head at a constant speed. The implication of CLV, as opposed to CAV, is that disc angular velocity is no longer constant, and the spindle motor needed to be designed to vary its speed from between 200 RPM on

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