| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology, capable of externally adjusting an output impedance of a photodetector IC (PDIC) connected to a flexible printed wiring board (FPC), in matching with the inductance and the capacitance of the FPC so as to suppress production of peakings, without attenuating a required signal band. SOLUTION: A signal, converted into a voltage through optical/voltage conversion by the PDIC 1, is given to the drain of a field effect transistor (FET) 4 from an output of an output circuit 3, and the source of the FET 4 is connected to an output terminal 7. The signal from the output terminal 7 is given to a signal processing board of the body via an equivalent circuit of the FPC 2 comprising a coil 5 and a capacitor 6. A gate of the FET 4 is connected to a variable voltage source VR. Although peaking is produced by an inductive component and a capacitive component of the FPC 2, by having a voltage applied to the variable voltage source VR and optimally adjusting the gate voltage of the FET 4 to use an ON-resistance of the FET 4, the peaking is suppressed. COPYRIGHT: (C)2007,JPO&INPIT
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