Aiming at problem that weak signal caused by upwelling is easily overwhelmed by sensor system noise before A/D conversion

the filtering

amplification and A/D conversion circuits are processed adopting integrated chip AD7195

reduce discrete device noise

differential amplifier

AC excitation and digital filters are integrated in AD7195 chip

but also has function of 24 bit high-precision A/D conversion. By building experimental apparatus

collect datas and analyze

test system accuracy. Experimental results show that error of the system is able to identify input signal is ± 0. 4μV

which meets design requirements.