| 摘要 |
PURPOSE:To realize an application of the preamplifier having a narrow dynamic range, by changing the frequency characteristics of the open loop of the preamplifier and the feedback loop into the low-range and high-range passing characteristics each having the cut-off frequency within each video band. CONSTITUTION:The optical signal entered the optical diode 1 is supplied to the preamplifier 9 via the MOS switching elements 5 and 6 which are controlled by the vertical and horizontal shift registers SR2 and SR5 each. The amplifier 9 possesses a feedback loop to feed its output signal back to the input side via the impedance Zf8. The open loop's frequency characteristics of the preamplifier is changed into the low-range passing characteristics having the cut-off frequency within the video band; while the frequency characteristics of the feedback loop is changed into the high-range passing characteristics having the cut-off frequency within the video band respectively. In such way, the output signal of the solid state image pickup element can be processed by means of a preamplifier having a narrow dynamic range, thus attaining a small size and the single power source. |
