| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable an easy adaptation to a new appropriate optical input level range even when a signal input level on an optical transmitter side is changed in an optical receiver receiving an optical signal. <P>SOLUTION: A photoelectric control circuit 54 is provided on a signal output side of a photoelectric conversion element 51 which converts an optical input signal into an electric signal. The photoelectric control circuit 54 switches over an operation level by a switchover switch 55 so as to accommodate to a plurality of operation levels, inputs the electric signal converted by the photoelectric conversion element 51 to a gain adjustment amplifying circuit 56, and adjusts the gain of the gain adjustment amplifying circuit 56 by detecting a light receiving voltage at the operation level set by the switchover switch 55. When an operation level of a system is changed, and an electric signal input level of the optical transmitter is changed; the switchover switch 55 is switched to adjust the operation level to a new operation level, and an electric signal at the same level is arranged to be outputted from the gain adjustment amplifying circuit 56 even when any operation level is selected. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
