| 摘要 |
<P>PROBLEM TO BE SOLVED: To easily perform fine adjustment in gain to be required in system adjustment without affecting a correction amount corresponding to optical transmission loss though there is the problem that it is difficult to perform the fine adjustment by an arrangement condition at every slave station, etc., in the conventional light receiving circuit for correcting the optical propagation loss. <P>SOLUTION: In the light receiving circuit, the MPU 14c of an integrated automatic correcting part 14 calculates an optical propagation loss correcting voltage value by interpolation processing referring to a correction data table on the basis of a detection voltage value corresponding to average light reception power from an A/D converting part 14b, performs an additional correcting operation on the basis of an additional correcting value which is manually input from a setting unit 17 to the optical propagation loss correcting voltage value, calculates a final correcting value so as to output it to a D/A converter 14d, and applies the obtained control voltage Vc to a voltage control variable RF attenuator 16. <P>COPYRIGHT: (C)2007,JPO&INPIT |
