CD/DVD player - Know everything !

It's a drive optical drive that reads through a laser diode optical discs called CDs or CD
It's a drive optical drive that reads through a laser diode optical discs called CDs or CD

The CD player

It's a drive optical drive that reads through a laser diode optical discs called CDs or CD, be it CD or computer CD-ROM.

When it is used to listen to music CDs, the CD player can be integrated into various types of portable devices or servants, to a radio handset, etc. It can also be a separate, portable device or domestic, to connect to a channel Hi-Fi, an audio amplifier or headphones.

Computer, the CD player is either in the form of an internal device in the central unit, or an external device connected to the computer by a USB
USB
The USB bus is also said to \Hot pluggable\, that is to say that you can connect and disconnect a USB with the PC on. The system installed on the PC (Windows, linux...) recognizes it immediately. The USB has a very interesting feature : it's the mode standby when not using the device. Also known as \Power conservation\ : Indeed the USB bus gets suspended after 3 ms if it is no longer used. During this mode, the co......
or FireWire
FireWire
FireWire is the trade name given by Apple to a multiplexed series interface, also known as the standard IEEE 1394 and also known as the interface i.LINK, trade name used by Sony. It is a computer bus carrying both data and command signals from the various connected devices.
It can be used to connect all kinds of bandwidth-friendly devices that require stable data throughput, especially in hard drives and digit......
port.

DVD player (or DVD player) is an optical disc drive used to exploit the digital data stored on DVDs. The arrival of the DVD Video (Digital Versatile Disc) revolutionized so this little world, which appeared in 17 aux √Čtats-Unis en 18 in Europe particularly in France.
Most DVD players can read several formats of optical discs.

Operation

Rotation of the disc

The disk rotates by a servo engine at variable speed. Indeed, whether the section of track1 is in the center or periphery, the length of the sectors is always the same, therefore, unlike the vinyl disc, the scrolling of the data in front of the playhead must be constant.
In simple speed, an area must be flown in 1/75th of a second. For a linear reading speed of 1.2 ms-1, the rotational speed varies from 458 tre min-1 to read the 50 mm diameter areas of the disk to 197 tr-min-1 to read the areas with a diameter of 116 mm (about)
For comparison, a drive with a speed 16 times higher (CD-Rom 16x player) will see the speed of its disc vary between 7,328 tre min-1 and 3,152 tremin-1.
Mechanical CD Philips with swivel arms.

Moving the head

The movement of the optical block is provided either by a swivel arm (Philips mechanics) or by a linear servo with very high precision because, on a possible total displacement of three centimeters4, it is able to adopt 600 different positions per millimeter.
A lens from a CD player.

Laser diode

The laser diode emits in the infrared and is used for both writing and reading; however, the power of the beam is different if it is a reader or an engraver (a few milliwatts in reading versus 24 mW for a quadruple-speed engraver), moreover, it varies according to the speed of engraving.

Optically directing beams

The laser diode emits a beam to a prism (which can be characterized as a semi-transparent mirror); this prism sends the beam back at right angles to direct it to the lenses. The beam reflected by the disk (in polycarbonate) passes through the prism to excite the photodiode.

Lenses

The optical focusing block is on a mobile device whose movements are controlled by electromagnets. This system allows the position adjustment (sliding setting) of the focusing lens (mounted on a moving coil) in relation to the disk. This package is the goal.
The lens, upstream of the lens, is used to concentrate the laser beam, so as to obtain a beam about one micrometer in diameter, in order to be able to read the microcuvettes (pits in English) of different lengths of the disc6.
Since the diameter of the beam is not significantly wider than the wavelength of the incident beam, the focus of the beam must therefore be extremely precise.
The manufacture of these lenses requires greater rigor but, unlike microscope lenses, for a single wavelength, that of the laser beam.

Photosensitive diode

This detects changes in reflected light. For a reader, this diode is used to read the disk information by detecting the variations of light received, characterized by the fronts generated by the succession of microcuvettes and intermediate smooth ranges (lands) of the disk.
The high-frequency signal picked up by this receptive cell is called an eye diagram.
Its decoding is used for several systems, including locating the position of the laser beam on the disk and assessing the speed of rotation of the disk, with a view to correcting it continuously (work of the enslavement circuits).
For an engraver, it is also used to control the engraving. For a CD, the captured binary rate is standardized at 4.3218 MHz.

DVD player


Computer, DVD players are a computer input devices. They may be internal, which is integrated in the housing, or external, installed in their own case and connected to the computer through USB
USB
The USB bus is also said to \Hot pluggable\, that is to say that you can connect and disconnect a USB with the PC on. The system installed on the PC (Windows, linux...) recognizes it immediately. The USB has a very interesting feature : it's the mode standby when not using the device. Also known as \Power conservation\ : Indeed the USB bus gets suspended after 3 ms if it is no longer used. During this mode, the co......
or FireWire
FireWire
FireWire is the trade name given by Apple to a multiplexed series interface, also known as the standard IEEE 1394 and also known as the interface i.LINK, trade name used by Sony. It is a computer bus carrying both data and command signals from the various connected devices.
It can be used to connect all kinds of bandwidth-friendly devices that require stable data throughput, especially in hard drives and digit......
connector, and powered electricity sector.

DVD players can be used in the salon to reproduce video content. They are then connected to a TV
Digital terrestrial TV
Two major types of broadcasting exist for television; the so-called analogue and digital television. The analogue television appeared the first. This is widely spread around the world. However, this type of diffusion is ageing and not very innovative.
For this reason analogue television is currently tending to disappear to give way to digital television. Digital television is largely based on analogue televisio......
through HDMI
HDMI
HDMI is a fully digital audio/video interface that transmits uncompressed encrypted streams. HDMI is used to connect an audio/video source (DVD player, Blu-ray player, computer or game console) to a high-definition TV.
HDMI supports all video formats, including standard, improved, high-definition definition and multichannel sound. HDMI encapsulanses video data by TMDS. Initially, the maximum HDMI transmission......
or SCART
The Peritel
PERITEL refers to a coupling device and an audio/video connector that has been mainly used in Europe. It simply plugs in devices (TVs) that have analog audio/video functions using a 21~pin connector.
There are three types of connectors : the socket on the devices, the male/male cord and the extension cord. Peritel connectors are more often found on equipment marketed in Europe. Today analogue television is b......
, S-Video, RCA
RCA
An RCA connector, sometimes called Cinch, is a type of electrical connector commonly used to transmit audio and video signals. The RCA name from the Radio Corporation of America, who designed it in the early 1940s for the internal connection of the reading head of the phonographs.
It has a simple design and low cost. The connecting plug is called RCA plug or Jack to phono, phonograph or C......
, and audio amplification by outputs analog audio system or by an optical type S/PDIF for digital sound cable.
The DVD video frames are also able to read the CD audio type, or even VCD / SVCD and, for the most recent, CDs and data DVDs containing media files in various formats (especially MP3 music, JPEG for photos (, and DivX for video).
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