| 摘要 |
PROBLEM TO BE SOLVED: To obtain sufficient S/N by suppressing a peak of frequency characteristic even when a photodiode is large in size. SOLUTION: An S/N ratio is improved through resonance by inputting the photosensitive current of the photodiode PD into an arithmetic amplifier 1 via inductance. Peak of frequency characteristic generated in this case can be suppressed through addition of a feedback type damping circuit, by connecting a network formed of a capacitor Cf and a resistor Rf2 between an output terminal and a non-inverted input terminal of the arithmetic amplifier 1. Accordingly, even when the photodiode PD is large in size, the peak of frequency characteristic is suppressed and sufficient S/N ratio is also obtained. COPYRIGHT: (C)2007,JPO&INPIT
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