| 摘要 |
PURPOSE:To obtain an absolute digital value, which is highly linerarly proportional to the quantity of incident light, by interrupting the incident light upon a photoelectric converter in a preset period, by guiding the interrupted light into the photoelectric converting element, by amplifying the electric signals and by eliminating the DC component which is generated by the converting means. CONSTITUTION:Optical converting means 1, which is composed of a supply power source for a photoelectric converting element 11 such as a photoconductive element, detects incident light 10, which is interrupted by a chopper 71, so that the quantity of the light may be converted into electric signals of voltage, which are fed to an amplifier 2. This amplifier 2 eliminates the DC component of the input signals and selectively amplifies only the AC component, which is then fed to an adder 3. This adder 3 adds a preset DC voltage to the AC component to generate a positive monopolar voltage, which is fed to an A/D converter 4. This converter 4 converts the input voltage into digital quantities, which are then fed to a memory device 5. On the other hand, the chopper 71 is turned by a drive motor 72 to interrupt the incident light in a preset period. Thus, it is possible to stably operate the A/D converter. |
