Abstract

Info

Title:: Design of acquisition circuit for weak surface electromyography signals

Author(s):: ZHOU Mingjuan1; WANG Yuyuan1; WANG Tiange1; RAN Li2; 1. Shanxi Railway Institute, Weinan 714000, China 2. School of Water Resources and Hydropower, Xian University of Technology, Xian 710048, China

Keywords:: Keywords: surface electromyography signal two-stage amplification high-order filtering interference suppression power-line noise

Abstract:: Abstract: Considering that surface electromyography signals (sEMG) has low frequency and is extremely vulnerable to interference, a signal acquisition circuit based on high-order filtering is designed. A two-stage amplification scheme is adopted in circuit for preventing the noise from being over-amplified. Two sets of 5th-order Sallen-Key is used in band-pass filtering, and the cascaded follows the order of odd first and even second, thereby avoiding mixing high-frequency leakage signals in the output signal and the stop-band descent speed reaches -100 dB/dec. In addition, the notch filter is equipped with an adjustable potentiometer to flexibly adjust the quality factor (Q value) in order to obtain the optimal signal acquisition. The results show that the circuit can not only achieve an amplification gain up to 60 dB, effectively extracting useful signals between 20 Hz and 500 Hz, but also effectively suppresses 50 Hz power-line interference, with a good anti-noise performance.