| 摘要 |
PROBLEM TO BE SOLVED: To make a means which detects the peak value of a reproducing signal on the positive side and a means which detects the peak value of the reproducing signal on the negative side common even when a reproducing signal level and a signal zone are different in recording information in a recording medium by means of a light source of different wavelength. SOLUTION: The reproducing signal at the time of the irradiation of a light from one light source and the reproducing signal at the time of the irradiation of a light from the other light source are selected and outputted by a selector 3, the reproducing signals are amplified and outputted by a variable gain amplifier 4, the peak value of the reproducing signals on the positive side is detected by a P/H6, the peak value of the reproducing signals on the negative side is detected by a B/H7, the direct current component value of the reproducing signals is detected by a LPF8, and the most adequate recording power is calculated by a power calculating part 9 based on at least two detected values. |
