| 摘要 |
PROBLEM TO BE SOLVED: To prevent a high frequency component from entering a power line by providing bypass means for bypassing the high frequency component included in an input signal and inputting only the input signal component, between an external signal line connected to an input unit, and an external power line and setting line connected to the input unit. SOLUTION: A high frequency component HN, included in an input signal S1 inputted into an input unit 201 of a laser driver 200, is bypassed by high frequency bypass circuits 11 and 12, comprising serial circuits, resistors 11A and 12A having a time constant substantially equal to the high frequency component, and capacitive elements 11B and 12B, so as not to mix the high frequency component HN in the laser driver 200. As a path P2 has an impedance greater than that of a path P1, an input signal line 80c, Vcc, and a GND line are separated with respect to the high frequency component. As the input impedance of the input unit 201 is high with respect to the high frequency component, the high frequency component is prevented from entering the power line. |
