Portable CD player
In 1982, Sony produced the industry's first portable CD player, the D-50 also called the 'Discman'. This CD player was released just one year after the introduction of CDs on the market, and soon other companies started to release their own portable devices. One of the major problems with the early portable CD players was something called skipping. Skipping consists of the laser inside the CD player temporarily losing its place on the CD, interrupting playback. In 1993 a solution to this was introduced in the form of Electronic skip protection, which caches a few seconds of audio in memory to reduce disruption from mechanical disturbance of the laser.[better source needed]
The basic features of a portable CD player are:
- Fast forward
- Hold (some models)
- Liquid crystal display
- Headphone/audio out socket
The play and pause feature allows the user to pause in the middle of the track (song) and resume it at the same place the listener left off at once the play button is hit again. The stop feature stops the track allowing the user to then switch tracks easily. The fast forward and rewind feature will either fast forward or rewind the track the amount of time you hold the button down. The liquid crystal display provides a visual of how much battery is left, what track (number) is currently playing, and the amount of time elapsed on the track. Some portable CD players can play CD-R/CD-RW discs and some can play other formats such as MP3-encoded audio.
How it works
Like a full-size CD player, a portable CD player reads the bumps and grooves using a laser. With its photocell (a device that detects any sort of light reflection given off of certain area), it determines whether there is a reflection of light given off from the CD when the laser hits. Depending on the light reflection, the photocell will return a 1 (if there is no reflection) or a 0 (if there is any light refection). When its laser hits a groove on a CD, it will not reflect any light, making it a 1. When its laser hits a bump or any other surface on the CD, a light reflection will appear making it a 0. The series of data from 0-1 on the CD is then transformed by a digital to analog converter, to recreate the shape of a sound wave. The headphones then amplify the sounds and then the audio is now able to be heard.
Issues with recordable CDs
Some portable CD players do not play recordable CDs (CD-R, CD-RW) because of the way that recordable CDs are recorded. a consumer-recorded CD is recorded by making marks in a thin layer of organic dye. Some portable CD players are unable to read this type of CD. For some users of CD-Rs, the solution to this is to burn the CD at a slower speed or use a different brand of recordable CDs.
Portable CD players are declining in popularity since the rise in popularity of digital audio players that play MP3 files including the iPod and smartphones. Before MP3 and digital audio players became popular, many switched over to MiniDisc as an alternative to CDs, due to the compact size of the MiniDisc format.
- CD player
- Portable DVD Player
- Personal stereo
- Portable audio player
- Portable media player
- Lungu, R. "History of the Portable Audio Player." 2008-11-27.
- Encyclopedia II - "Electronic Skip Protection - History"
- "Portable CD Players Product Guide" http://www.jr.com/product/productGuide.jsp?contentPath=/Content/media/html/productGuides/Audio/portableCDPlayers.html
- "How CDs Work"
- "CD player won't play my burned cds." 2006-02-17
- Wallop, H. Portable CD players make a comeback 12-07-08.