Struer, Denmark--Just by looking across the room, could you tell the difference between your VCR, tape deck, receiver, or CD player? They're all in flat black boxes with controls--usually too many--on the front.
Nobody could mistake Bang & Olufsen's BeoSound 9000 for anything but what it is: a sleek CD player.
"BeoSound 9000 is a revolt against indifference and black boxes," says David Lewis, award-winning designer for Bang & Olufsen. "The way things have become, you can hardly tell whether you are looking at a toaster or a typewriter."
Launched this summer, the BeoSound 9000 can be positioned seven different ways, such as vertically on a floor stand, horizontally on the wall, or placed on a shelf. No matter how you orient the unit, you can unplug and turn around the concealed operating panel for your convenience. The 12-character display flips to read the way the control panel does.
The CD carriage contains the playing mechanism. Press the button for CD 6, and the carriage whisks quickly yet silently to that disk. It moves so fast that you need wait no more than 4.5 seconds from the current song to one selected on any other disk. In fact, the carriage would hit sports car speeds of 100 km/hour within 5.8 seconds, if the rails were only long enough.
Best of all, the BeoSound 9000 lets you choose your CD music visually. Not only can you see which discs are loaded, you can replace the discs not being played without stopping the music. And, after playing a song, the carriage replaces the CD to within one degree of how you placed it in the holder. You can store this position, as well as the name of the disc and your favorite tracks, in the system's 200-disc memory.
The visual appeal of the player disguises the high level of technology that makes this performance possible. Eight digital servo systems, five microprocessors, five dc motors, six digital-to-analog converters, and 15 IR sensors work behind the scenes to bring you a music system that appeals to the eye and the ear.
http://www.designnews.com/article/CA151171.html
Friday, July 20, 2007
5 Great Reasons for Choosing an MP3 Audiobook
In a recent survey by the Audio Publishers Association (APA) nearly 25% of the US population is listening to audio books. This is backed up by sales figures for 2005 of $871 million. Some experts are predicting sales for 2006 to come in as high as $2 billion. This massive leap in sales is largely due to the increasing popularity of MP3 audio books in digital download format.
So, why are audiobook versions a more convenient way to "read" a book?
1) You save time, because you can listen to an audio book anywhere and everywhere, and you can even do other things at the same time. You can listen when driving to and from work, when walking the dog, cycling, gardening, working around the house or at the computer, exercising at home or at the gym, and so on. The possibilities are endless.
According to a recent survey, in the USA a person is driving an average of 1 hour and 13 minutes daily, which means over 440 hours a year for each driver, or 11 full-time working weeks. This is huge! Imagine how many things you could learn during this time by simply having your MP3 player with audio books at hand.
2) If you love reading but don't have enough time, audio books can give you the opportunity to read many more books than you would otherwise have time for. Audio books are a great way to fill the "dead" moments we all have in our lives.
With the compact size of modern MP3 players, compared to CD or cassette players, you always have room to take your mp3 player with you. Plus you don’t have to worry about losing or changing cd’s or tapes either.
3) Audio books are good for older, ill or recovering people and can be a wonderful gift for someone in a nursing institution. This is a gift they can remember and enjoy time after time. The massive market place for audio books ensures that everyone can find a topic or subject that appeals to them.
4) Audio books can be a blessing for blind people, disabled people or people with impaired vision. Everyone should have the chance to experience and enjoy a book and in many cases, this is the only way for such persons to do it.
Spoken books can help these people improve their education, help them develop new hobbies and habits and greatly enrich their life, both personally and professionally.
5) Probably the most important skill a child can ever acquire is the ability to read, and audio books can be easily used to stimulate literacy in children. Children can follow the story in a paper book whilst listening to it being dramatically read aloud. Or they could listen just to gain and improve vocabulary and communication skills. If you want to instil in your child the love of reading, audio books can be an excellent start.
There are many more benefits of using audio books, but even these few reasons should be enough to convince you to enter the exciting world of the spoken books.
http://www.articlecube.com/Article/5-Great-Reasons-for-Choosing-an-MP3-Audiobook/69075
So, why are audiobook versions a more convenient way to "read" a book?
1) You save time, because you can listen to an audio book anywhere and everywhere, and you can even do other things at the same time. You can listen when driving to and from work, when walking the dog, cycling, gardening, working around the house or at the computer, exercising at home or at the gym, and so on. The possibilities are endless.
According to a recent survey, in the USA a person is driving an average of 1 hour and 13 minutes daily, which means over 440 hours a year for each driver, or 11 full-time working weeks. This is huge! Imagine how many things you could learn during this time by simply having your MP3 player with audio books at hand.
2) If you love reading but don't have enough time, audio books can give you the opportunity to read many more books than you would otherwise have time for. Audio books are a great way to fill the "dead" moments we all have in our lives.
With the compact size of modern MP3 players, compared to CD or cassette players, you always have room to take your mp3 player with you. Plus you don’t have to worry about losing or changing cd’s or tapes either.
3) Audio books are good for older, ill or recovering people and can be a wonderful gift for someone in a nursing institution. This is a gift they can remember and enjoy time after time. The massive market place for audio books ensures that everyone can find a topic or subject that appeals to them.
4) Audio books can be a blessing for blind people, disabled people or people with impaired vision. Everyone should have the chance to experience and enjoy a book and in many cases, this is the only way for such persons to do it.
Spoken books can help these people improve their education, help them develop new hobbies and habits and greatly enrich their life, both personally and professionally.
5) Probably the most important skill a child can ever acquire is the ability to read, and audio books can be easily used to stimulate literacy in children. Children can follow the story in a paper book whilst listening to it being dramatically read aloud. Or they could listen just to gain and improve vocabulary and communication skills. If you want to instil in your child the love of reading, audio books can be an excellent start.
There are many more benefits of using audio books, but even these few reasons should be enough to convince you to enter the exciting world of the spoken books.
http://www.articlecube.com/Article/5-Great-Reasons-for-Choosing-an-MP3-Audiobook/69075
Numark Intros MP102 Rackmount MP3 CD Player
Designed for mobile DJs and club owners in search of a cost-effective, rackmountable solution to a wide variety of music playback requirements, the new MP102 plays both standard CD audio and MP3 CDs, provides buffered Anti-Shock memory protection, delivers seamless looping, pitch control with a pitch bend wheel, stereo RCA and digital outputs, balanced outputs, and an EQ section.“The new MP102 is a feature-packed unit and the perfect solution for mobile DJs and clubs in search of a comprehensive player offering MP3 support,” said Numark CEO John O’Donnell. “With its rackmount capability, the MP102 can be transported easily or secured in a club’s equipment cabinet. ”
With the ability to play both standard audio CDs and MP3 CDs, the new MP102 provides outstanding versatility. With support for the MP3 media format, DJs can now fit substantially more music onto a single CD; dramatically reducing the volume/weight of the music library they transport—making their work easier. The MP102 also features buffered Anti-Shock memory protection to ensure the music plays exactly as it should, even when the dance floor is packed. And DJs will appreciate the ability to create seamless loops—for both CD audio and MP3 files as well as true buffered instant start and stutter start capability with settable stutter points.
The unit features a large, easy-to-read, backlit LCD that includes text display for identifying song names, BPM counters, and other pertinent information. The user-friendly MP102 also provides ± 8/16% pitch bend capability via its pitch bend/jog wheel. For programming music sets, the MP102 supports true continuous playback and is also track sequence programmable. With support for both folders and ID3 tags, locating and identifying tracks is easy. This unit also provides balanced and unbalanced output capability, plus a digital output for interfacing with external digital equipment.
The MP102 rackmountable CD player is will be available Q2 of 2006 with a suggested retail price of $399.
http://www.synthtopia.com/content/2006/01/27/numark-dj-cd-player/
Compact Disc Player
Background
A compact disc, also popularly known simply as a CD, is an optical storage medium with digital data recorded on its surface. A compact disc player is a device that reads the recorded data by means of an optical beam and accurately reproduces the original information (music, pictures, or data). Because the player reads the information by optical means, there is no physical wear and tear on the disc. The basic technology used in all compact disc players is essentially the same, whether the player is designed for audio, video, or computer applications. This article will focus on players designed for audio (specifically, home audio) applications.
The history of the compact disc system can be traced back to the early 1970s, when rapid advancement in digital electronics, laser optics, and large scale integration (LSI) technologies took place. Many companies started exploring the possibility of storing audio signals in optical form using digital rather than analog means. A practical method of modulating the audio signals was found using theories published in 1948 by a scientist named Claude E. Shannon. This method, known as Pulse Code Modulation (PCM), samples audio signals during a short time interval and then converts the samples into numerical values for storage in digital format.
The storage of audio in digital format (known as audio encoding) requires large amounts of data. For example, storing one second of audio information requires one million bits of data. Optical discs capable of storing billions of bits of data in a very small area were found ideal for such applications. An optical disc can store up to one million bits of data on an area as small as a pinhead. Once the technologies for recording and storing digital audio were found, manufacturers started looking for ways to read and process the data stored in such a small area. Experiments with laser devices (a laser emits a very narrow beam of light capable of focusing on a very small area) proved quite successful. The development of LSI techniques meant that the huge amount of data stored on the disc could be processed fast enough to provide continuous music. The stage was now set for the development of a complete compact disc system.
Although many companies participated in early research and experimentation with the various technologies involved in a compact disc system, two companies—Sony of Japan and Philips of the Netherlands—are credited with successfully merging these technologies into a complete system. The two companies collaborated to develop specific standards for the compact disc system, and a consortium of 35 manufacturers agreed to adopt these standards in 1981. The first compact disc players were introduced in the European and Japanese markets in late 1982 and in the United States in early 1983.
Raw Materials
A compact disc player is a very sophisticated piece of electronic equipment. The simple exterior contains complex interior mechanisms to read and process audio signals into very clear and crisp music. The various components include a housing cabinet, an optical pick-up assembly, and printed circuit boards (PCBs), which contain microchips that direct the electronic processes of the system.
The cabinet that houses the maze of components is usually made of light, reinforced aluminum. The laser is a small glass tube filled with gas and a small power supply to generate a laser beam, while the photodiode—a semiconducting part that the light that is reflected from the compact disc into an electrical signal—is generally made of silicon or germanium. The lenses and mirrors in the optical pick-up are made of highly polished glass or plastic. This assembly is housed in its own plastic enclosure. The majority of the electronic components—resistors, transistors, and capacitors—are contained on microchips attached to PCBs. The base material of these components is usually silicon. The hardware that connects the various subassemblies together consists of a variety of metal and plastic nuts, screws, washers, pulleys, motors, gears, belts, and cables.
Design
A compact disc is a 4.75 inch-diameter (12.065 centimeters) polycarbonate plastic disc containing approximately 74 minutes of audio information. Not all the information on the disc is music; some of it is used for error detection, synchronization, and display purposes. Information on a CD is encoded on a spiral track in the form of indentations called lands and pits that represent binary highs and lows. It is these indentations that the CD player's laser "reads."
Conceptually, the design of a CD player resembles that of a phonograph (record) player. Like a record, the compact disc is rotated on a turntable, and the audio is read by a pick-up device. However, unlike a record player, the motor does not rotate the turntable at a constant speed but adjusts it in accordance with the distance of the pick-up from the center of the turntable. Furthermore, the pick-up device in a CD player is not a mechanical stylus (a needle) but an optical laser beam that does not come into physical contact with the compact disc. This laser focuses its beam on the disc track that contains the lands and pits, and the CD player's detector (the photodiode) senses the difference between the light reflected from the lands and that reflected by the pits. The photodiode turns this reflected light into an electrical signal. Relayed to the electronic circuit board, this signal is then converted back to sound.
There are basically three subassemblies in a compact disc player: the disc drive mechanism assembly; the optical pick-up assembly; and the electronic circuit board assembly, which coordinates the other systems inside the player and which includes the servo mechanism and data decoding circuitry. By sending signals to the servo mechanism, the circuit board adjusts the motor speed, focusing, and tracking of the optical pick-up; manages the flow of data to the decoding circuitry; and provides display information in response to the various buttons on the control panel.
The disc drive mechanism consists of a spindle that holds the CD and a motor that rotates it. The motor, called the spindle motor, is mounted underneath the plastic disc loading tray or turntable. A separate motor mounted on the chassis (the base or frame of the CD player) moves the loading tray in and out of the player; this is done by means of a gear that is attached to the motor and that also operates a larger gear to raise and lower a clamp for holding the disc in place.
The optical pick-up consists of a laser, a photodiode, and various lenses and mirrors. The entire subassembly slides back and forth on rails and is controlled by the servo mechanism that receives directing signals from the circuit board. The optical pick-up is usually located underneath the clamp that positions the disc, while the motor that moves the assembly is mounted on the chassis close to the rails. The mechanism works by directing a laser beam through lenses and mirrors onto the underside of the compact disc. The lenses and mirrors keep the beam properly focused. If the beam hits a pit on the disc, no light is reflected and the photodiode remains disengaged. If the beam hits a land, light is reflected back through the lenses and mirrors onto the photodiode, which then generates an electrical signal. This signal is transferred to the electronic circuit board assembly, where it is converted by the data decoding system into audio signals for playback.
The electronic circuit board assembly consists of printed circuit boards that contain the circuitry for the servo mechanism, which operates the optical pick-up system, data decoding, and control system. There are many integrated circuits chips, microprocessors, and large scale integrated components on the board assembly.
A key assembly in a compact disc player is the optical pick-up assembly. It is situated on rails so that it can move back and forth underneath the compact disc. It works by directing a laser beam at the CD; if the laser hits a land, the reflected light then travels to the photodiode, which generates an electrical signal. In turn, the signal moves to the CD player's circuit board, which converts the signal into music.
A key assembly in a compact disc player is the optical pick-up assembly. It is situated on rails so that it can move back and forth underneath the compact disc. It works by directing a laser beam at the CD; if the laser hits a land, the reflected light then travels to the photodiode, which generates an electrical signal. In turn, the signal moves to the CD player's circuit board, which converts the signal into music.
The Manufacturing
Process
In today's manufacturing environment there is no single method of manufacture and assembly. Products are increasingly made as subassemblies and brought together as larger subassemblies or as the final product. Robotics and computer run lines allow for virtually any part to be installed in any state of the subassembly at any point in the process. The sequence can be changed in minutes to allow for modifications or quality control check points. The manufacturing process detailed here, therefore, follows a similar approach to the actual manufacturing process used in the industry. The process is first described in terms of the various subassemblies and then the description details how the various subassemblies are brought together to make the final product.
Optical pick-up subassembly
* 1 Purchased from outside contractors, the laser and the photodiode are installed beneath the disc clamp. The various lenses and mirrors in the assembly must be properly spaced and aligned so that they can focus and direct light as necessary. The whole assembly is then housed in a plastic case. The case is made by the one of the usual plastic forming processes such as extrusion or injection molding, while the lenses and mirrors (usually silicon) are cut into the proper shape and then finely polished with abrasives. The semiconducting photodiode is made by preparing and polishing a substance such as silicon or germanium and then adding impurities to create layers. Electrical contacts are then added. After the optical components are in position, the gears and belt that will help to position the optical pick-up are put in place.
Disc drive subassembly
* 2 Next, the motor that will move the optical pick-up is connected to the gears and belt and placed on the chassis. The loading tray is now centered, and the spindle motor that will rotate the disc is installed. After the clamp to which the optical pick-up has been attached is positioned adjacent to the loading tray, the tray, clamp, and pick-up motor are installed in the loading drawer, which is placed in the CD player's cabinet.
Electronic circuit board subassembly
* 3 Last to be assembled are the electronic components. Designed by engineers using computer-aided design (CAD) packages, the circuit boards consist of a copper-clad base that has a pattern transferred onto it(masking) through screen printing or a similar method. After being coated with a photosensitive material, the patterned areas are etched away chemically to create a multi-layered board—the layers comprise the various transistors and capacitors that make up the circuits. The tiny microchips (usually made of silicon) that are mounted on the board are made in the same way, except on a much smaller scale. Depending on the manufacturer, the CD player may have one large circuit board or several smaller boards. After they have been attached to the panel or panels, the circuits are attached to the CD player's front control panel, the switch assembly, and finally the power supply.
Final assembly
* 4 Once the various subassemblies are ready, they are connected and interfaced together to complete the final assembly. Most of the work performed at this stage is done by human workers. The CD player is now tested and sent for packaging.
Quality Control
As previously noted, a compact disc player is a very sophisticated device, and strict quality control measures are adopted from the initial to the final stage of the manufacture to ensure the proper functioning of the player in accordance with industry standards.
Because so many of the components in a compact disc player are made by specialized vendors, the player manufacturer must depend on these vendors to produce quality parts. Some of the most crucial elements are those in the optical pick-up assembly. The lenses and mirrors used in the laser pick-up, for instance, are made of high quality glass, and human contact must be avoided during the manufacturing process to keep their surfaces clean and smudge free. Similarly, the electronic circuit components must be made in a "clean room" environment (containing special air filters as well as clothing requirements), because even a single dust particle can cause malfunctioning in the circuitry. The circuit boards and chips are tested at many levels by diagnostic machines to pinpoint faults in the circuits.
As for quality control by the player manufacturer, the disc drive assembly is inspected for proper alignment of the motor, spindle, loading tray, and the various gears. In addition, the optical pick-up is checked for proper alignment of lenses and the laser beam. Once the subassemblies are tied together in the cabinet, all wiring connections are inspected for proper electrical contact and correct interface with the other components. Visual inspections to check belts, pulleys, and gears are an integral part of the quality control process. The final inspection consists of playing a test disc that generates special signals and patterns, enabling workers to track down faults in the system. In addition, the various front panel switches and buttons are checked to ensure that they perform the functions indicated and display the appropriate information on the panel.
The Future
The CD system technology has come a long way in the last few years, and new applications for compact disc systems are being discovered every day. The market has already seen the introduction of CD-ROMs, CD-Videos and CD-Interactive. The latest product to attract consumer attention is Kodak's Photo-CD, which can display photographs on television and computer screens. These pictures can be edited or cropped by the user, just like clip art images.
Audio CD systems will see the introduction of many new features in the coming years. Players featuring advanced remote control functions are now in the development stage.
The housing for a CD player includes a top cover or "bonnet' and a front control panel. The compact disc rests on a loading tray that slides in and out of the player.
The housing for a CD player includes a top cover or "bonnet' and a front control panel. The compact disc rests on a loading tray that slides in and out of the player.
These functions will allow the user to display information on the remote control unit itself, such as song titles, artist names, and the actual lyrics of the songs. Compact discs capable of both recording and playback, like a cassette tape, are also in the works. The CD's vast storage capabilities also lend itself to many broad-based multimedia applications, and it is quite possible that compact discs will become the common medium of data exchange for all audio, video, and computer applications.
http://www.madehow.com/Volume-1/Compact-Disc-Player.html
A compact disc, also popularly known simply as a CD, is an optical storage medium with digital data recorded on its surface. A compact disc player is a device that reads the recorded data by means of an optical beam and accurately reproduces the original information (music, pictures, or data). Because the player reads the information by optical means, there is no physical wear and tear on the disc. The basic technology used in all compact disc players is essentially the same, whether the player is designed for audio, video, or computer applications. This article will focus on players designed for audio (specifically, home audio) applications.
The history of the compact disc system can be traced back to the early 1970s, when rapid advancement in digital electronics, laser optics, and large scale integration (LSI) technologies took place. Many companies started exploring the possibility of storing audio signals in optical form using digital rather than analog means. A practical method of modulating the audio signals was found using theories published in 1948 by a scientist named Claude E. Shannon. This method, known as Pulse Code Modulation (PCM), samples audio signals during a short time interval and then converts the samples into numerical values for storage in digital format.
The storage of audio in digital format (known as audio encoding) requires large amounts of data. For example, storing one second of audio information requires one million bits of data. Optical discs capable of storing billions of bits of data in a very small area were found ideal for such applications. An optical disc can store up to one million bits of data on an area as small as a pinhead. Once the technologies for recording and storing digital audio were found, manufacturers started looking for ways to read and process the data stored in such a small area. Experiments with laser devices (a laser emits a very narrow beam of light capable of focusing on a very small area) proved quite successful. The development of LSI techniques meant that the huge amount of data stored on the disc could be processed fast enough to provide continuous music. The stage was now set for the development of a complete compact disc system.
Although many companies participated in early research and experimentation with the various technologies involved in a compact disc system, two companies—Sony of Japan and Philips of the Netherlands—are credited with successfully merging these technologies into a complete system. The two companies collaborated to develop specific standards for the compact disc system, and a consortium of 35 manufacturers agreed to adopt these standards in 1981. The first compact disc players were introduced in the European and Japanese markets in late 1982 and in the United States in early 1983.
Raw Materials
A compact disc player is a very sophisticated piece of electronic equipment. The simple exterior contains complex interior mechanisms to read and process audio signals into very clear and crisp music. The various components include a housing cabinet, an optical pick-up assembly, and printed circuit boards (PCBs), which contain microchips that direct the electronic processes of the system.
The cabinet that houses the maze of components is usually made of light, reinforced aluminum. The laser is a small glass tube filled with gas and a small power supply to generate a laser beam, while the photodiode—a semiconducting part that the light that is reflected from the compact disc into an electrical signal—is generally made of silicon or germanium. The lenses and mirrors in the optical pick-up are made of highly polished glass or plastic. This assembly is housed in its own plastic enclosure. The majority of the electronic components—resistors, transistors, and capacitors—are contained on microchips attached to PCBs. The base material of these components is usually silicon. The hardware that connects the various subassemblies together consists of a variety of metal and plastic nuts, screws, washers, pulleys, motors, gears, belts, and cables.
Design
A compact disc is a 4.75 inch-diameter (12.065 centimeters) polycarbonate plastic disc containing approximately 74 minutes of audio information. Not all the information on the disc is music; some of it is used for error detection, synchronization, and display purposes. Information on a CD is encoded on a spiral track in the form of indentations called lands and pits that represent binary highs and lows. It is these indentations that the CD player's laser "reads."
Conceptually, the design of a CD player resembles that of a phonograph (record) player. Like a record, the compact disc is rotated on a turntable, and the audio is read by a pick-up device. However, unlike a record player, the motor does not rotate the turntable at a constant speed but adjusts it in accordance with the distance of the pick-up from the center of the turntable. Furthermore, the pick-up device in a CD player is not a mechanical stylus (a needle) but an optical laser beam that does not come into physical contact with the compact disc. This laser focuses its beam on the disc track that contains the lands and pits, and the CD player's detector (the photodiode) senses the difference between the light reflected from the lands and that reflected by the pits. The photodiode turns this reflected light into an electrical signal. Relayed to the electronic circuit board, this signal is then converted back to sound.
There are basically three subassemblies in a compact disc player: the disc drive mechanism assembly; the optical pick-up assembly; and the electronic circuit board assembly, which coordinates the other systems inside the player and which includes the servo mechanism and data decoding circuitry. By sending signals to the servo mechanism, the circuit board adjusts the motor speed, focusing, and tracking of the optical pick-up; manages the flow of data to the decoding circuitry; and provides display information in response to the various buttons on the control panel.
The disc drive mechanism consists of a spindle that holds the CD and a motor that rotates it. The motor, called the spindle motor, is mounted underneath the plastic disc loading tray or turntable. A separate motor mounted on the chassis (the base or frame of the CD player) moves the loading tray in and out of the player; this is done by means of a gear that is attached to the motor and that also operates a larger gear to raise and lower a clamp for holding the disc in place.
The optical pick-up consists of a laser, a photodiode, and various lenses and mirrors. The entire subassembly slides back and forth on rails and is controlled by the servo mechanism that receives directing signals from the circuit board. The optical pick-up is usually located underneath the clamp that positions the disc, while the motor that moves the assembly is mounted on the chassis close to the rails. The mechanism works by directing a laser beam through lenses and mirrors onto the underside of the compact disc. The lenses and mirrors keep the beam properly focused. If the beam hits a pit on the disc, no light is reflected and the photodiode remains disengaged. If the beam hits a land, light is reflected back through the lenses and mirrors onto the photodiode, which then generates an electrical signal. This signal is transferred to the electronic circuit board assembly, where it is converted by the data decoding system into audio signals for playback.
The electronic circuit board assembly consists of printed circuit boards that contain the circuitry for the servo mechanism, which operates the optical pick-up system, data decoding, and control system. There are many integrated circuits chips, microprocessors, and large scale integrated components on the board assembly.
A key assembly in a compact disc player is the optical pick-up assembly. It is situated on rails so that it can move back and forth underneath the compact disc. It works by directing a laser beam at the CD; if the laser hits a land, the reflected light then travels to the photodiode, which generates an electrical signal. In turn, the signal moves to the CD player's circuit board, which converts the signal into music.
A key assembly in a compact disc player is the optical pick-up assembly. It is situated on rails so that it can move back and forth underneath the compact disc. It works by directing a laser beam at the CD; if the laser hits a land, the reflected light then travels to the photodiode, which generates an electrical signal. In turn, the signal moves to the CD player's circuit board, which converts the signal into music.
The Manufacturing
Process
In today's manufacturing environment there is no single method of manufacture and assembly. Products are increasingly made as subassemblies and brought together as larger subassemblies or as the final product. Robotics and computer run lines allow for virtually any part to be installed in any state of the subassembly at any point in the process. The sequence can be changed in minutes to allow for modifications or quality control check points. The manufacturing process detailed here, therefore, follows a similar approach to the actual manufacturing process used in the industry. The process is first described in terms of the various subassemblies and then the description details how the various subassemblies are brought together to make the final product.
Optical pick-up subassembly
* 1 Purchased from outside contractors, the laser and the photodiode are installed beneath the disc clamp. The various lenses and mirrors in the assembly must be properly spaced and aligned so that they can focus and direct light as necessary. The whole assembly is then housed in a plastic case. The case is made by the one of the usual plastic forming processes such as extrusion or injection molding, while the lenses and mirrors (usually silicon) are cut into the proper shape and then finely polished with abrasives. The semiconducting photodiode is made by preparing and polishing a substance such as silicon or germanium and then adding impurities to create layers. Electrical contacts are then added. After the optical components are in position, the gears and belt that will help to position the optical pick-up are put in place.
Disc drive subassembly
* 2 Next, the motor that will move the optical pick-up is connected to the gears and belt and placed on the chassis. The loading tray is now centered, and the spindle motor that will rotate the disc is installed. After the clamp to which the optical pick-up has been attached is positioned adjacent to the loading tray, the tray, clamp, and pick-up motor are installed in the loading drawer, which is placed in the CD player's cabinet.
Electronic circuit board subassembly
* 3 Last to be assembled are the electronic components. Designed by engineers using computer-aided design (CAD) packages, the circuit boards consist of a copper-clad base that has a pattern transferred onto it(masking) through screen printing or a similar method. After being coated with a photosensitive material, the patterned areas are etched away chemically to create a multi-layered board—the layers comprise the various transistors and capacitors that make up the circuits. The tiny microchips (usually made of silicon) that are mounted on the board are made in the same way, except on a much smaller scale. Depending on the manufacturer, the CD player may have one large circuit board or several smaller boards. After they have been attached to the panel or panels, the circuits are attached to the CD player's front control panel, the switch assembly, and finally the power supply.
Final assembly
* 4 Once the various subassemblies are ready, they are connected and interfaced together to complete the final assembly. Most of the work performed at this stage is done by human workers. The CD player is now tested and sent for packaging.
Quality Control
As previously noted, a compact disc player is a very sophisticated device, and strict quality control measures are adopted from the initial to the final stage of the manufacture to ensure the proper functioning of the player in accordance with industry standards.
Because so many of the components in a compact disc player are made by specialized vendors, the player manufacturer must depend on these vendors to produce quality parts. Some of the most crucial elements are those in the optical pick-up assembly. The lenses and mirrors used in the laser pick-up, for instance, are made of high quality glass, and human contact must be avoided during the manufacturing process to keep their surfaces clean and smudge free. Similarly, the electronic circuit components must be made in a "clean room" environment (containing special air filters as well as clothing requirements), because even a single dust particle can cause malfunctioning in the circuitry. The circuit boards and chips are tested at many levels by diagnostic machines to pinpoint faults in the circuits.
As for quality control by the player manufacturer, the disc drive assembly is inspected for proper alignment of the motor, spindle, loading tray, and the various gears. In addition, the optical pick-up is checked for proper alignment of lenses and the laser beam. Once the subassemblies are tied together in the cabinet, all wiring connections are inspected for proper electrical contact and correct interface with the other components. Visual inspections to check belts, pulleys, and gears are an integral part of the quality control process. The final inspection consists of playing a test disc that generates special signals and patterns, enabling workers to track down faults in the system. In addition, the various front panel switches and buttons are checked to ensure that they perform the functions indicated and display the appropriate information on the panel.
The Future
The CD system technology has come a long way in the last few years, and new applications for compact disc systems are being discovered every day. The market has already seen the introduction of CD-ROMs, CD-Videos and CD-Interactive. The latest product to attract consumer attention is Kodak's Photo-CD, which can display photographs on television and computer screens. These pictures can be edited or cropped by the user, just like clip art images.
Audio CD systems will see the introduction of many new features in the coming years. Players featuring advanced remote control functions are now in the development stage.
The housing for a CD player includes a top cover or "bonnet' and a front control panel. The compact disc rests on a loading tray that slides in and out of the player.
The housing for a CD player includes a top cover or "bonnet' and a front control panel. The compact disc rests on a loading tray that slides in and out of the player.
These functions will allow the user to display information on the remote control unit itself, such as song titles, artist names, and the actual lyrics of the songs. Compact discs capable of both recording and playback, like a cassette tape, are also in the works. The CD's vast storage capabilities also lend itself to many broad-based multimedia applications, and it is quite possible that compact discs will become the common medium of data exchange for all audio, video, and computer applications.
http://www.madehow.com/Volume-1/Compact-Disc-Player.html
Recovering Scratched CDs
Every user has had trouble with a scratched CD. In the case of data CDs (CD-ROM), the drive cannot properly read the CD, giving rise to reading errors. In the case of audio CDs, the CD skips when we play it.
The first thing to do when coming across a CD with a read error is to clean it, to check whether it the error is not being caused by a dirty surface. You can even wash the CD gently with a little detergent, using your fingers to clean it (avoid sponges, since they can scratch the CD). If the error persists, try reading or playing the CD on another drive. If another drive (or CD player, in the case of audio CDs) gives the same result (read error or skipping, in the case of audio CDs), it will mean that the CD is scratched.
Looking against the light, the recording surface (the flip side of the label) of a CD with this kind of trouble will allow you to easily see one or more existing scratches. A CD's data is recorded on a metal layer inside it, a silvered layer on commercial CDs, which is usually golden on CD-Rs. This metal layer is inset in a transparent plastic covering (polycarbonate), used to protect the CD's metal layer and allow printing a label on the side not used for reading.
A CD-ROM drive or CD player utilizes a laser beam to read the metal layer. This laser beam crosses the plastic layer and reads the metal layer. If the plastic layer is scratched, the beam will be unable to pass through it, resulting in a read error or skipping the music. In other words, the data to be read are still in the CD, the trouble lies in the layer of plastic.
As the CD's contents are preserved, a scratched CD can be recovered by polishing its plastic surface. If, after carrying out the above cleansing, the CD persists in giving reading errors, just polish the CD with toothpaste. That's right, toothpaste. It works wonders, and you won't spend a fortune buying professional cleaning kits. Polish the scratches with a cotton swab, rubbing gently the paste-imbued swab over the scratches until they disappear or until you notice that you have removed them as far as possible. Sometimes the paste may cause new scratching, but it will be merely superficial and easily removed. After clearing the scratches, wash the CD in water.
If there are still scratches that the toothpaste has not managed to removed, use a metal polish (Brasso) in the same way as described above. Finally, rub Vaseline on the CD, very gently (do not press hard), from moving out from the centre to the rim.
The last step will be testing the CD. If it starts working properly, great. If not, repeat the above procedure, looking for the scratch that is causing the error and concentrating your polishing efforts on it.
http://www.hardwaresecrets.com/article/77
The first thing to do when coming across a CD with a read error is to clean it, to check whether it the error is not being caused by a dirty surface. You can even wash the CD gently with a little detergent, using your fingers to clean it (avoid sponges, since they can scratch the CD). If the error persists, try reading or playing the CD on another drive. If another drive (or CD player, in the case of audio CDs) gives the same result (read error or skipping, in the case of audio CDs), it will mean that the CD is scratched.
Looking against the light, the recording surface (the flip side of the label) of a CD with this kind of trouble will allow you to easily see one or more existing scratches. A CD's data is recorded on a metal layer inside it, a silvered layer on commercial CDs, which is usually golden on CD-Rs. This metal layer is inset in a transparent plastic covering (polycarbonate), used to protect the CD's metal layer and allow printing a label on the side not used for reading.
A CD-ROM drive or CD player utilizes a laser beam to read the metal layer. This laser beam crosses the plastic layer and reads the metal layer. If the plastic layer is scratched, the beam will be unable to pass through it, resulting in a read error or skipping the music. In other words, the data to be read are still in the CD, the trouble lies in the layer of plastic.
As the CD's contents are preserved, a scratched CD can be recovered by polishing its plastic surface. If, after carrying out the above cleansing, the CD persists in giving reading errors, just polish the CD with toothpaste. That's right, toothpaste. It works wonders, and you won't spend a fortune buying professional cleaning kits. Polish the scratches with a cotton swab, rubbing gently the paste-imbued swab over the scratches until they disappear or until you notice that you have removed them as far as possible. Sometimes the paste may cause new scratching, but it will be merely superficial and easily removed. After clearing the scratches, wash the CD in water.
If there are still scratches that the toothpaste has not managed to removed, use a metal polish (Brasso) in the same way as described above. Finally, rub Vaseline on the CD, very gently (do not press hard), from moving out from the centre to the rim.
The last step will be testing the CD. If it starts working properly, great. If not, repeat the above procedure, looking for the scratch that is causing the error and concentrating your polishing efforts on it.
http://www.hardwaresecrets.com/article/77
Subscribe to:
Posts (Atom)