Method of and apparatus for the reading of magnetically stored information

摘要

A magnetic storage medium is read by incident polarized light and reflected outgoing light defining a common plane. The polarized incident light preferably has a polarization vector at 40 DEG to 50 DEG to this plane and at the storage medium, the magnetization is in a direction perpendicular to the plane. The preamplified output signal VM from the photodiode transducing the outgoing light beam has a fixed value VO subtracted therefrom where VO is a function of the sensitivity and resolving power of the electronic circuitry. The signal VM-VO is then amplified and processed to represent the stored data.