Patent ID: 6744700
Filing Date: 2004-06-01
Classification: G11B

Abstract:
An optical output adjustment apparatus for adjusting an output level of a reproducing laser beam, in a signal reproducing device which adopts a magnetic wall movement detection reproducing method, irradiates the reproducing laser beam onto a magneto-optical information recording medium on which data is recorded by recording marks having different recording lengths according to a predetermined modulation method, and magnifies a magnetic sector by magnetic wall movement, thereby to perform reproducing of the data, characterized in thatthe optical output adjustment apparatus comprises: a light source for emitting the reproducing laser beam; reproducing signal detector means for detecting a high-frequency reproducing signal consisting of a high-frequency component in a reproducing signal obtained by reproducing the magneto-optical information recording medium; signal amplitude level detector means for detecting an amplitude level of the high-frequency reproducing signal; comparator means for comparing the amplitude level with a predetermined threshold value; and optical output control means for adjusting the reproducing laser beam to an output level which makes the amplitude level equal to or higher than the predetermined threshold value.