| 摘要 |
PURPOSE:To increase the reproducible number of times and to make a device small in size and a simple in structure by using a reproduced light beam pulse modulated with the ratio of pulse width to a prescribed frequency and a prescribed pulse period. CONSTITUTION:In this reproducing method, a reproduced light is pulse modulated having light intensity of a mW order as shown in the figure (a), a higher pulse frequency >= ten times than the maximum frequency contained in a recorded signal as is shown in the figure (b) is used for modulation. By irradiating a recording medium having the recorded signal as shown in the figure (b) with the pulse modulated reproduced light, the reflected light intensity complied with the recorded signal is obtained as shown in the figure (c). After photoelectrically converted by a photodetector, the reflected light beam is transmitted through a low-pass filter and a signal voltage as shown in the figure (d) is obtained. At this time, the ratio of the pulse width of the pulse modulated reproduced light to the pulse period is made smaller than 1/1000. |
