| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the adjustment time of an AGC amplification factor in an optical receiver having a function (AGC) of amplifying the amplitude of an electric signal output from a photodetector (photodiode). <P>SOLUTION: The amplification factor control (AGC amplification factor control) of a variable gain amplifier 33 is performed only when receiving a preamble added to communication data from a transmission side, instead of continuously performing amplification factor control of the variable gain amplifier 33. While the preamble is not being received, the amplification factor of the variable gain amplifier 33 is fixed. With such processing, the AGC amplification factor is not increased during an optical modulation OFF period (period when a signal level is zero), and the AGC amplification factor in the previous preamble period can be retained and continued till the next preamble period. By this, it is possible to reduce the adjustment time (setup time) of the AGC amplification factor at the next preamble reception time. <P>COPYRIGHT: (C)2013,JPO&INPIT |
