| 摘要 |
PURPOSE:To provide high-reliability reception processing without restriction by an analog circuit. CONSTITUTION:At an optical signal reception control circuit 11, an optical idle signal is extracted by a frequency discrimination circuit 113. Since any abnormality is detected by a signal polarity time detection circuit 114 when time for the polarity of that signal to be fixed is longer than a specified value, an abnormality detecting operation and the optical signal reception processing can be performed without overlapping the time so that high-reliability reception processing can be provided. Further, since there is no analog signal circuit, this circuit is immune from noises and the circuit layout is easily performed. |
