| 摘要 |
PURPOSE:To determine the most suitable erasing power more practically, easily and correctly by changing erasing power by the same modulating system as the one used actually for the recording of information and measuring a bit error ratio. CONSTITUTION:A magneto-optical recording medium 1 is rotated by a spindle motor 2 and the information is recorded to or reproduced from the medium 1 by an optical pickup 3 and a magnet 4 to give a bias magnetic field. A signal read by the pickup 3 is amplified by an amplifier 5 and the bit error ratio (BER) is counted by an inspector 7. By using this measuring system, data are recorded by the same modulating system as the one at the time of the actual recording of the information, they are erased by different erasing power, the BER is measured and thus, a power/BER diagram is prepared. By obtaining the erasing power corresponding to a permissible BER from this diagram, the most suitable erasing power can be determined even when a measured thing is a recording medium with a format. |
