| 摘要 |
PURPOSE:To eliminate errors due to the instability of spark discharge and thereby to improve precision, by detecting a breakdown voltage in a spark gap at every time of the spark discharge while leaving a discharge circuit as it is, and by applying compensation to a photometric output. CONSTITUTION:When a spark discharge occurs between CG, a charged voltage of a capacitor C works wholly between AG, and thereby a spark discharge occurs between AG. The occurrence of the spark discharge is detected by an optical detector D, and a signal from said detector is amplified and shaped by an optical detection circuit 1 and is delivered therefrom as a pulse signal to a time-difference detection circuit 2. Meanwhile a gate pulse is sent from a control circuit K to the time-difference detection circuit 2, and the time difference between the two pulses is detected therein. This time-difference detection circuit 2 is a counter which starts counting at the rise of the gate pulse from the control circuit K and stops the counting at the arrival of the pulse from the optical detection circuit 1, and it counts a clock pulse. In a data processing circuit 3, a compensating operation is applied to a photometric output sent from a photometric circuit 4 of a spectrophotometer, by using the data on the time difference sent from said time-difference detection circuit 2. |
