| 摘要 |
PURPOSE:To discriminate the presence of a carrier wave in a reception section by transmitting a signal to be modulated by amplitude modulation as an optical signal and generating a signal similar to the modulated signal when the transmitted optical signal is received by a reception section and obtaining a high level output by a carrier signal detection section. CONSTITUTION:A bias voltage is applied to a base of the 1st transistor (TR) 10 by resistive elements 4, 6 and when a data signal is inputted to a signal input terminal 5, the emitter current is controlled. When a data is at a high level, a large carrier signal is outputted as the modulated signal as shown in figure (a) corresponding to the data signal and when the data is at a low level, a small carrier signal is outputted and a signal as shown in figure (b). A light emitting element 8 is driven by a current by inputting the modulated signal in figure (b) to the base of a TR 12 and an optical signal is outputted from the element 8. Thus, a signal shown in figure 2(b) is generated even at the reception section. |
