| 摘要 |
PROBLEM TO BE SOLVED: To enable a single light signal transmission/reception device of different light interface to transmit or receive light signals by a method, wherein digital electric signals are converted into light signals which are sent to an optical fiber cable, and the light signals are varied in light intensity in response to control signals given from the outside. SOLUTION: A light signal transmission device 10 is equipped with constant current sources 11 and 12, a selective control circuit 13, a buffer circuit 14, a differential amplifier 15, and a light-emitting device 16, wherein the direct current of the constant current source 11 or 12 selected by the selective control circuit 13 is switched by a differential amplifier 15 to pulse-drive the light-emitting device 16. Digital electric signals 18 are inputted into the light signal transmission device 10 through an input terminal Vin , pass through the buffer circuit 14 which enables the signals 18 to be subjected to waveform shaping, shifted in potential level, differentiated, and then sent to a light-emitting device drive means, and generate a current for driving the light-emitting device 16 via the differential amplifier 15 which switches a drive current. With this setup, light signals 17 outputted from the light signal transmission device 10 can be turned into light signals whose light intensity is intentionally selected out of two different levels of intensity. |
