摘要 |
Time-divisionally-multiplexed light receiving signals are sampled at a predetermined time interval as they are, and then converted into digital data. Then, address is determined based on an index signal as a standard of the time-divisional multiplexing, and the data are sequentially stored in a data memory. When the data are sequentially read out, change of quantity of the data is obtained to determine a period having the smallest change in quantity as an effective period. Then, the data included in the effective period are selected and separated to a sample side beam, reference side beam and cutoff period. Thus, the multiplexed light receiving signals are accurately separated by the digital data.
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