| 摘要 |
PURPOSE:To obtain an output signal corresponding linearly to an input signal by providing a capacitor to cut off the DC component of a light signal and a coil to ground the DC component of the light signal. CONSTITUTION:The light signal is detected by a photodiode PD, and is outputted to an amplifier AP through a capacitor C. In the case where the light signal whose DC component is large is detected by the diode PD, the DC component is cut off by the capacitor C, and only a signal component as essential information is inputted to the amplifier AP, and is amplified, and is supplied to prescribed processing. The cut off DC component of the light signal is grounded through the coil L. Thus, since the DC component of the input signal is cut off by the capacitor C, the DC bias point of the amplifier AP, that is, the reference voltage of the amplification of the input signal comes not to vary. Accordingly, the output signal whose input/output characteristic corresponds linearly to the input signal can be obtained. |
