CD player is also called CD player or laser player. It first came into the eyes of consumers in 1982. It is a kind of intelligent high-fidelity stereo equipment controlled by microcomputer. It has a variety of advanced technologies, for example, Laser technology, digital technology, computer technology and a variety of new components have the advantages of high-density recording, long playback time, simple operation and fast song selection.

The theory of CD player：

The CD player is mainly composed of laser pickup and turntable system, servo system, signal processor, information storage system and control system.

The laser pickup is the key part of the CD player. It is composed of a semiconductor laser, an optical system and an electrical detector. The laser is a low-power light-emitting diode. The laser beam emitted is projected onto the record information through an optical lens system.

There are many pits on the record. When the light spot hits the pit, because the reflected light is relatively weak, the signal picked up by the photoelectric detector is relatively small. When the photoelectric hits the aluminum film without pits, the reflection The light is relatively strong, the signal picked up by the photodetector is relatively large, so that the corresponding pits generate corresponding high and low level electrical pulse signals at the output of the detector.

These signals pass through the RF amplifier, and the internal comparator obtains serial digital signals of 1 and 0, and is added to the digital signal and processing circuit for demodulation, error correction processing, etc., and the processed data is added to the digital-to-analog converter, In this way, the converter becomes an analog sound output, and the sound is emitted.