Patent ID: 7981264
Filing Date: 2011-07-19
Classification: G01N

Abstract:
1. An apparatus for sensor calibration, comprising: a first sensing element located in a monitoring solution for outputting a first sensing signal; a second sensing element located in said monitoring solution for outputting a second sensor signal; a first instrumental differential amplifier for outputting said first sensing signal, wherein a first input end of said first instrumental differential amplifier connects to said first sensing element, and a second input end connects to ground; a second instrumental differential amplifier for outputting said second sensing signal, wherein a third input end of said second instrumental differential amplifier connects to said second sensing element, and a fourth input end connects to said ground; a voltage shifting circuit coupled to the output end of said second instrumental differential amplifier for shifting said second operation sensing signal and outputting a third signal proportional to a sensor drift; a third instrumental differential amplifier, wherein a fifth input end of said third instrumental differential amplifier connects to the output end of said first sensing element, and a sixth input end connects to said voltage shifting circuit for obtaining the potential difference between said first sensing signal and said third signal; and a reference element located in said monitoring solution, wherein one end of said reference element connects to said ground for providing a constant reference voltage.