| 摘要 |
PURPOSE:To improve the quality of a reproduced information signal by preventing the duty ratio of pulses of the reproduced information signal from varying owing to a lengthwise increase in the size of pits formed on an optical disk. CONSTITUTION:The modulated pulse signal A of the information signal from an information signal source is supplied to a rising edge detecting circuit 2 and a falling edge detecting circuit 3 to generate a rising edge pulse B and a falli9ng edge pulse C. The rising edge pulse B is delayed by a specific quantity through a delay circuit 4 to set an SR-FF6 and the falls edge pulse C is delayed by a specific quantity through a delay circuit 5 to reset the SR-FF6. Here, the delay quantity of the delay circuit 4 is made larger than the delay quantity of the delay circuit 5 to make the pulse width D of the modulated pulse signal outputted by the SR-FF6 shorter than that of the modulated pulse signal A; and their delay quantities are properly set to obtain pitch length on the optical disk corresponding to the pulse width of the modulated pulse signal A. |
