| 摘要 |
PURPOSE:To reduce the variation of an output by releasing the holding of the currents of a semiconductor laser at every fixed time. CONSTITUTION:An output signal from an edge detecting circuit 17 detecting the rise edge of a frame synchronous signal FSYNC reaching to a low level during the period of frame recording is inputted to an edge detecting circuit 14 as a timing signal through an OR circuit 18 and an AND gate 19. Pulses are outputted at every fixed time T (such as several sec) because an edge detecting circuit 20 detects the rise edge of an output signal from a monostable multivibrator 21 and triggers the monostable multivibrator 21, and inputted to the edge detecting circuit 14 as a timing signal through the AND gate 19. Accordingly, not only an enable state is released on the rise of the frame synchronous signal FSYNC but also the state of stand-by is released at every fixed time T even at a stand-by mode. |
