| 摘要 |
PURPOSE:To efficiently drive a laser diode by means of a filter and, at the same time, to supply a driving pulse of a period in which noise caused by returning light is less to a laser diode by changing the oscillation frequency of a variable oscillator in accordance with the length of an optical path. CONSTITUTION:A first filter 14 for inhibiting a driving pulse from a drive circuit 15 for recording is provided between a drive circuit 13 for reproduction and laser diode 2 and a second filter 16 for inhibiting a driving pulse from the circuit 13 is provided between the circuit 15 and the diode 2, Then a detecting means 11 detects the length of the optical, path of laser light from the diode 2 to a magneto-optical disk M and changes the oscillation frequency of a variable oscillator 12 connected to the circuit 13 based on the detecting output. |
