Optical Signal Processing And Servo Processing

VCD and DVD player are replacing every bygone audio and video products for their high quality of audio and video, and being thought as the preferred signal resource in the home theater system.This article introduces mainly digital encoding theory and digital correction theory, and researches how every servo circuit is driving motors and coils.EFM and EFM+ encoding technology is used to settle the problem that the 16 bits data of audio and video will form a long non-pit interval in the disc after MPEG encoding. Because a long non-pit interval will cause it difficult to control the disc track's following. And a steady clock signal is necessary to judge the numbers of zero.During optical pickup unit reading information from a disc, the badness and damage and dirty of the disc will cause wrong information. CIRC correcting technology is used to check and correct errors.4 conditions is necessary for optical pickup unit reading information from a disc:1 .the focus servo system;2.the tracking servo system;3.the traverse motor servo system;4.the spindle motor servo system.Nowadays, there are many versions of relative literature.