| 摘要 |
PURPOSE:To correct an asymmetry potential with high accuracy without reducing the size of a measuring range by digitally storing the asymmetry potential and then converting the same to a voltage for correction. CONSTITUTION:The signal occurring in the asymmetry potential is outputted from a differentials amplifier 3 and an up-down counter 6 counts clock pulses when a switch 7 is turned on while only the asymmetry potential is generated by a standard soln. having a zero ion concn. the count content is converted by a D/A converter 8 and is inputted to the differential amplifier 1. The level of the output signal from the amplifier 1 begins to fall. The output from the amplifier 3 attains a zero level when the output voltage from the converter 8 coincides with the asymmetry potentials and therefore, a comparator 4 stops the outputting of the signal so that the counting operation of the counter 6 is interrupted. The amplifier 1 offsets the asymmetry potential signal by receiving the potentials signal from the converter 8 and the amplifier 3 outputs the potential difference signal occurring in only the ion concn. when a sample is measured after the switch 7 is turned off at this point of the time. |
