| 摘要 |
PURPOSE: To optimally control a writing intensity even though the width of a writing area varies by deciding the position of a DC level to the maximum and minimum value of reading signals and obtaining analyzing signals based on this. CONSTITUTION: Information signals Vi is converted into binary signals Vefm EFM-modulated to control a switch 62, and input signals I1 and Is are alternately transmitted to a comparing circuit 48. By this way, the intensity of writing beam 13 is switched to writing intensities I1 and Is, an information pattern corresponding to signals Vefm is recorded into a medium 4. Next, a reading beam 53 is modulated with the information pattern, made to be reading signals V1 with a detector 64, and transmitted to an analyzing circuit 65. Signals Va, expressing the range of the positional deviation of the DC level from the central value between the minimum and maximum value of reading signals V1, are generated with the circuit 65 and transmitted to an adding circuit 67 via an integrating circuit 66. And signals (is), consisting of the sum of integrating signals and signals (io) corresponding to a given intensity, are obtained. Therefore, the continuous control is executed so that the writing intensity (Is) becomes the optimal value. |
