| 摘要 |
PURPOSE: A circuit for restoring a receiving call of a laser transmission device is provided to amplify a received weak signal by using a high gain amplifier and a low pass filer, and to remove noise of the amplified signal, thereby increasing an S/N(Signal to Noise) ratio. CONSTITUTION: A receiving element(21) receives a laser beam incident on a light receiving part of a laser transmission device, and outputs an electric signal. An electric signal conversion amplifier(22) converts the electric signal outputted from the receiving element(21) into a voltage, and amplifies the voltage. The first low pass filter(23) removes noise of a high frequency voltage outputted from the electric signal conversion amplifier(22). A signal amplifier(24) amplifies a low level signal of the noise-removed high frequency voltage to a high level signal. The second low pass filer(25) removes the second noise of the high level signal amplified in the signal amplifier(24). |
