| 摘要 |
PURPOSE:To make unnecessary externally mounted logarithmic amplifier, by connecting the logarithmic amplifier between the matrix circuit and the Y direction multiplexer. CONSTITUTION:The code signal 1 is inputted to the X direction multiplexer 1 and a given X line is selected and grounded. Similarly, the Y direction multiplexer 4 selects the Y line with the code signal and the output of the photo detector is picked up from the Y direction multiplexer. To the Y line of the matrix circuit consisting of the X lines 2a to 2n and the Y lines 6a to 6n, the logarithmic amplifiers 9a to 9n having the log diodes 8a to 8n are connected, and the output of the photo detectors 7a to 7n is delivered to the Y multiplexer 4 after logarithmic compression. The logarithmic voltage outputted from the multiplexer 4 is code-converted to the digital signal at the A/D converter 10. Thus, exgernal mounting of logarithmic amplifiers can not be made unnecessary. |
