| 摘要 |
PURPOSE:To obtain constant data even without signal light by providing an oscillator, adding an output of the oscillator and the output of a photodetector, inputting the result to a frequency demodulator and obtaining an output from an outputterminal of the frequency demodulator. CONSTITUTION:When signal light exists, it is received by a photodetector 1, which converts the signal light into an electric signal, the signal is amplified by an amplifier 2 and the output of the amplifier 2 and the output of an oscillator 3 are added by an adder 4. Data is obtained at an output terminal by a frequency demodulator 5 and a voltage comparator 6. When no signal light exist, data with consecutive '1' is obtained at the output terminal by the frequency demodulator 5 and the voltage comparator 6. |
