Non-amplifying ECG signal acquisition system based on Σ-Δ A/D

ECG signal is a very weak signal acquired on the surface of body. In traditional ECG signal acquisition system, to get a high-SNR ECG signal, it must use all kinds of high-performance op-amp, which leads to the acquiring circuits complex and unstable. Furthermore, almost all op-amps more or less have nonlinear distortion and other disadvantages. In this paper, a non-amplifying method to acquire a high-SNR ECG signal was proposed. It is based on 24 bit Σ-Δ A/D embedded in a high performance mixture signal ARM processor-ADuC7060. The system has high SNR up to 74.8 dB, and low nonlinear distortion, original ECG can be acquired.