Bandwidth reduction in writeable optical data storage apparatus

摘要

Apparatus for reading data from an optical medium having improved settling time characteristics and reduced bandwidth requirements is disclosed. The apparatus includes a front facet detector for producing a front facet monitor signal from a laser light beam; first and second detectors for producing first and second data signals, respectively; and a first gain control circuit responsive to the front facet monitor signal to produce a gain adjusted front facet monitor signal. The apparatus further includes a second gain control circuit responsive to the first data signal and the gain adjusted front facet monitor signal to produce a first gain adjusted data signal; a third gain control circuit responsive to the second data signal and the gain adjusted front facet monitor signal to produce a second gain adjusted data signal; circuitry responsive to the first and second gain adjusted data signals to produce a magneto-optic data signal as a function of the difference between the first and second gain adjusted data signals; or to produce a combined data signal as a function of the sum of the first and second gain adjusted data signals and responsive to the gain adjusted front facet monitor signal and the combined data signal to produce a write-once data signal as a function of the difference between the gain adjusted front facet monitor signal and the combined data signal.