| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical transmission reception circuit with a circuit configuration independently of a transmission bit rate. SOLUTION: An electrooptic conversion section 11 converts an electric signal into an optical signal and provides the output of the optical signal according to a clock signal CLK IN. A frequency voltage conversion section 13 gives a voltage proportional to a frequency of the clock signal CLK IN to an optoelectric conversion section 12. A preamplifier 21 and a main amplifier 26 amplify the received optical signal and a timing extract section 27 extracts a clock signal CLK OUT from the amplified signal. An identification recovery section 28 recovers a timing of a received signal by the clock signal CLK OUT and provides an output. The resistance of a feedback receiver 22 of the preamplifier 21 is changed according to the output voltage of the frequency voltage conversion section 13 and then the gain and the band of the preamplifier 21 are controlled. A low pass filter 23 has a configuration of an RC circuit, and the resistance of a resistor 24 changes with an output voltage of the frequency voltage conversion section 13 and hence the cut-off frequency is controlled. |
