| 摘要 |
PURPOSE:To improve the availability of an optical thyristor valve by using a signal synchronous with the rise part of the drive signal of a light emitting source to detect (sampling) the light quantity of said light emitting source and monitoring the deterioration of the light emitting source by an on-line system. CONSTITUTION:When a light emitting source driving signal INP is set at a high level, the light emitting sources 51-5n are turned on. Then monitor light guides 41-4n send the optical signals for monitor to a photoelectric converting circuit L/E of an optical monitor circuit 60. While a multivibrator MUL is set at the rise of the signal INP and then reset after a set time T and this output signal is sent to a differentiating circuit DIF. A pulse CON is delivered at the fall of the output signal and then turned into a control signal of a sampling/holding circuit SRH. Thus the output of an amplifier circuit AMP for detected light quantity is sampled and held when said pulse CON has a high level and a low level respectively. therefore the sampling action is always carried out when a time T passed from the rise of the signal INP. Then the variation of the detected light quantity owing to the variance of the sampling time can be avoided by setting the time T at a time point when the light emitting source is steady transiently.
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