公开(公告)号：SG70556A1

公开(公告)日：2000-02-22

申请号：SG1996004914

申请日：1993-05-19

Applicant: IBM

Inventor： JAQUETTE GLEN ALAN ,  TAYEFAH MOROVAT

IPC: G11B11/10 ,  G11B7/005 ,  G11B7/13 ,  G11B11/105 ,  G11B13/00 ,  G11B13/04 ,  G11B11/12 ,  G11G11/10

Abstract: A circuit for simultaneously detecting both MO and ROM signals reflected from an optical disk so that both signals are present and useable without switching from one to the other. The circuit eliminates switching time and switching transients. Two photodetectors are arranged to sense P and S components of polarized light in order to stimulate a differential amplifier and produce an output representative of MO recorded data. A second amplifier is connected to at least one of the photodetectors to produce an output representative of ROM recorded data and also representative of defects in the MO portion of the optical disk.