| 摘要 |
PURPOSE:To eliminate the influence of noise by a method wherein the output of a circuit sample-holding error signals is sample-held by the second sample hold circuit. CONSTITUTION:Power control signals of a semiconductor laser 2 and monitor signals by a monitor diode 3 are inputted to an error detection circuit 4. The signal of the circuit 4 drives the laser 2 via the first and second sample hold circuits 5 and 6 and drive circuit 7. Modulated signals turn a transistor 9 on and off via delay circuit 9, thus performing the on-off operation of the laser 2. Besides, the modulated signal drives the first and second monostable multivibrators 13, 15 and sample-holds the error signals in the circuit 5 only when the modulated signals are at high level, and then sample-holds the output of the circuit 5 in the circuit 6 by averaging said output. |
