Do you know about CD player

                                                          Do you know about CD player?

The CD player is actually the CD player that we often say in our daily life, and some people call it a CD player 

Precautions

It is an intelligent high-fidelity stereo audio equipment controlled by a microcomputer. It adopts advanced laser technology, digital technology, computer technology and various new components. It has high-density recording and long playback time (up to 60~75 minutes). ), easy operation, quick selection and so on. It can reproduce recorded content realistically, with distinct layers and a sense of presence. Its sound technical indicators are very high, the dynamic range is large, the frequency response width is 5~2000Hz, and the distortion is as small as 0.003%.

CD player is mainly composed of laser pickup and turntable system, servo system, signal processing system, information storage system and control system. The laser pickup is a key component of the CD player, which consists of a semiconductor laser, an optical system and an electrical detector. The laser is a low-power (MW-level) AIGAS laser diode. The emitted laser beam is projected onto the information surface of the record through the optical lens system. Since many pits are recorded on the record, when the light spot hits the pit, Because the reflected light is weak, the signal picked up by the photoelectric detector is small; when the light spot hits the aluminum film without pits, the reflected light is strong, and the signal picked up by the photoelectric detection is large, which corresponds to the presence or absence of pits. The output of the detector generates electrical pulse signals of corresponding high and low levels, and then passes through the RF amplifier, and the internal comparator obtains serial digital signals of "1" and "0", and adds them to the digital signal and processing circuit for demodulation. , frame synchronization signal detection, error correction processing, etc., add the processed data to a digital-to-analog converter (D/A), and the converter outputs an analog sound signal.

Mirror-bright CDs are made of ultra-thin aluminum or gold sound film with a protective layer of PVC plastic. Like floppy disks and hard disks, CDs can store information in the form of binary data (a data pattern consisting of "0"s and "1s"). To store data on an optical disc, you must first convert the data into binary with the help of a computer, and then use a laser to engrave the data pattern on a flat, reflective disc. The small pits engraved by the laser on the disc represent "1". Blank space represents "0". When reading data from a CD disc, a directional beam (laser) moves rapidly across the surface of the disc. A computer or CD player that reads data from a disc looks at each point the laser passes through to determine if it reflects the laser. If it doesn't reflect the laser (there's a little pit there), then the computer knows it represents a "1". If the laser is reflected back, the computer knows the point is a "0". These thousands or millions of "l"s and "0s" are then restored to music by a computer or a CD player.

At present, CD players are already very common audio playback devices. According to their appearance, they can be divided into desktop and portable.

Written by : Davecl Audio

The Audio Equipments Manufacturer

www.davecl.com