The invention discloses a method and a
system for eliminating
direct current offset between electrodes based on a chopping technology. The method comprises the following steps: step S1, outputting an electroencephalogram
signal after chopping modulation and a
direct current offset
signal between the electrodes; s2, outputting
direct current offset current between the electrodes; s3, extracting an integral direct current offset
signal; s5, the electroencephalogram signals enter a
chip amplification module to be amplified and demodulated, the electroencephalogram signals are returned to an original electroencephalogram
signal frequency band, and original electroencephalogram signals are obtained; s6, filtering the original electroencephalogram signals through a low-pass filter to obtain
noise-filtered electroencephalogram signals; and S7, transmitting the
noise-filtered electroencephalogram signal into a digital-to-analog converter, and converting the
noise-filtered electroencephalogram signal into a
digital signal. The direct-current
servo circuit effectively suppresses direct-current offset between the electrodes, compared with a traditional direct-current
servo circuit, the process
delay is reduced, meanwhile, the
capacitance value of the input
capacitor in the circuit is the same as that of the feed-forward
capacitor, an ABBA type
layout arrangement mode can be adopted, and process errors in the
chip manufacturing process are effectively avoided.