Optical recording/reproducing apparatus
AssigneeNEC Corporation
InventorHajime Kobayashi
Life of this patent
Estimating the term…
Abstract
An optical recording/reproducing apparatus includes a monitor sensor for sensing the amount of emission from a laser diode or optical head. The output of the monitor sensor is routed through a non-inverting wide-band amplifier and an inverting amplifier to an envelope detector. The envelope detector detects peak values out of the input signal and delivers them to a current amplifier via an amplifier and a comparator. The current amplifier feeds a current corresponding to the input to the laser diode. This current corresponds to erasing power. The apparatus senses the emission conditions of the laser diode between the start and end of the recording operation so as to cause erasing power to constantly coincide with a reference value.
Claims9
An optical recording/reproducing apparatus comprising:
- mean value detecting means for detecting a mean value in a binary modulation condition of an output of an optical head;
- minimum value detecting means for detecting a minimum value in the binary modulation condition;
- and
- input current setting means for setting a current to be input to said optical head in accordance with the mean value and the minimum value,
- wherein said minimum value detecting means comprises:
- a non-inverting wide-band amplifier for amplifying the output of said optical head;
- an inverting amplifier for inverting an output of said non-inverting wide-band amplifier;
- and
- an envelope detector for detecting an envelope of an output of said inverting amplifier.
An optical recording/reproducing apparatus comprising:
- mean value detecting means for detecting a mean value in a binary modulation condition of an output of an optical head;
- minimum value detecting means for detecting a minimum value in the binary modulation condition of the output of said optical head;
- and
- input current setting means for setting a current to be input to said optical head in accordance with the mean value and the minimum value,
- wherein said minimum value detecting means comprises:
- a wide-band amplifier for amplifying an output of said optical head;
- and
- an envelope detector receiving an output of said wide-band amplifier for detecting an envelope of a signal portion corresponding to the minimum value.
An optical recording/reproducing apparatus comprising:
- a mean value detector, said mean value detector detecting a mean value in a binary modulation condition of an output of an optical head;
- a minimum value detector, said minimum value detector detecting a minimum value in the binary modulation condition;
- and
- an input current setter, said setter setting a current to be input to said optical head in accordance with the mean value and the minimum value,
- wherein said minimum value detector comprises:
- a non-inverting wide-band amplifier for amplifying the output of said optical head;
- an inverting amplifier for inverting an output of said non-inverting wide-band amplifier;
- and
- an envelope detector for detecting an envelope of an output of said inverting amplifier.
Dependencies are inferred from the claim text.