A biopotential signal acquisition system comprising an analog readout unit configured to receive an analog biopotential signal and to extract an analog measured biopotential signal and an analog reference signal, and an ADC unit configured to provide a digital version of the analog measured biopotential signal and the analog reference signal. The system also includes a first digital filter unit comprising a cascaded integrator-comb filter configured to provide a first digital filtered version of the digital measured biopotential signal and the reference signal, and a second digital filter unit configured to calculate a digital motion artifact estimate based on the first digital filtered version signals.