| 摘要 |
PURPOSE:To obtain light emission intensity similar to the time of low speed even when an LED is driven at high speed, and to realize long distance reach by lowering the duty ratio of a carrier signal by making the duty ratio of a subcarrier signal be 50% at least. CONSTITUTION:A driving pulse to be impressed upon an input terminal 1 is inversion-amplified by a buffer amplifier consisting of a transistor(TR) Q1, resistors R1, R2 and a gate diode D1, and the TR Q2 turns on/off as receiving the output of the TR Q1, and drives the LED 2. A signal to be impressed upon the input terminal 1 is the signal (c) that the RZ signal (a) of pulse width PW is pulse-amplitude-modulated PAM) by a subcarrier (b) whose duty ratio is 50%. Thus, because the pulse forward current of the LED of a light transmitter, etc., is increased by a PAM wave using the subcarrier whose duty ratio is 50% at least, the luminance of a light intensity modulated wave can be increased, and the light output of it can be increased. |
