| 摘要 |
PURPOSE:To output a faithful signal waveform with a few roundings, and to stably record and reproduce a signal whose waveform length is short by providing a switch which directly inputs the signal currents for recording of a laser output current driving means to a light source by by-passing a current leakage prevention filter at the time of recording. CONSTITUTION:At the time of reproduction/recording, a laser output current driving means 1 outputs signal modulation currents A/B for reproduction/ recording and a reproduction/recording control signal, and switches 3 and 6 are turned on and off/off and on by the control signal. Therefore, at the time of reproduction, the currents A are allowed to pass through a current leakage prevention filter 4, and a semiconductor laser 7 is driven by the currents obtained after the currents A are superimposed on high frequency currents outputted from a high frequency oscillation circuit 2. Also, at the time of recording, the circuit 2 is stopped, and the semiconductor laser 7 is directly driven by the currents B by by-passing the filter 4 by a by-pass circuit 5. Thus, the laser 7 can be driven by the faithful signal waveform with a few roundings, and the signal whose waveform length is short can be stably recorded and reproduced. |
