| 摘要 |
PURPOSE:To add and rerecord new information while reproducing previously recorded information by setting up time order radiating three optical beams to an optional specific point on a medium in accordance with the movement of the medium to the order of 1st-3rd optical beams, i.e. the order of reproducing, erasing and recording. CONSTITUTION:The 1st optical beam 14 for reproducing information recorded on the information recording medium, the 2nd optical beam 12 for erasing the information and the 3rd optical beam 15 for recording new information are projected on respectively different positions on the medium. Information previously recorded on the medium is reproduced by the 1st beam 14, decoded by a decoder 42 and mixed with new information by a mixer 40, the mixed information is encoded again by an encoder 48 and the encoded information is recorded on the original position of the medium by the 3rd beam 15. The information is erased by the 2nd beam 12 within the decoding and encoding time. Consequently, new information can be added and rerecorded while reproducing the previously recorded information.
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