Magneto-optic data storage system with differential detection channels having separate gain control circuit

摘要

An apparatus and method for detecting a data signal read from a magneto-optic (MO) storage medium. First and second detected signals are generated from first and second portions, respectively, of a radiation beam reflected from the medium. First and second gain control circuits are coupled to the first and second detectors, respectively. Each of the gain control circuits is operative to alter the gain of a signal path of the corresponding detected signal in response to a control signal which varies in accordance with a difference between the corresponding detected signal and a reference signal. The reference signals in each gain control circuit may be a common reference voltage level. A signal difference circuit produces a data signal corresponding to the difference between the detected signals.