| 摘要 |
PURPOSE:To easily obtain a stable output by providing a changeover means to switch an input level of an AGC(Automatic Gain Control) amplifier stepwise based on the output of the AGC amplifier. CONSTITUTION:The signal outputted from the AGC amplifier 3 is adjusted stably by using a switching circuit 8 switching the input level stepwise with a feedback signal from the AGC amplifier 3. Thus, the unified circuit is constituted without requiring any external component. Thus, a stable output is obtained easily by the AGC amplifier 3 over a wide range of the inputted optical power. Moreover, the level adjustment is not troublesome and processed in a short time and the necessity of installation space is evaded. |
