Gather And Design The Processor Of Surface EMG Signal

Surface electromyographic(sEMG) is the electrical activity of the nervous system in an integrated overlay performance at the surface of the skin,which contains information about the functional of muscles and nerves. With the rapid development of modern science and technology, sEMG has been deeper and more accurate understanding by the scientists, and is widely used in many areas such as basic medical research, rehabilitation engineering, clinical diagnosis.Diaphragmatic is the body’s most important muscle in breathing.the signal reflect the functional status of the respiratory system,and it plays an important role in disease diagnosis,monitoring and evaluation of respiratory function.This paper will study the characteristics of sEMG,and design a diaphragmatic EMG acquisition system base on the electrode surface.Because of sEMG is a kind of weak electrical signal, it can easily introduce other interfering signals during collecting.The design of a high anti-interference ability of the circuit is the first issue of this design considerations. In this paper, differential amplifier circuit and right leg drive circuit are designed by LF347 operational amplifier, effectively suppress common mode interference. And to filter out the signal of the high frequency, low frequency and power frequency noise,the high-pass filter, low pass filter and 50 Hz frequency notch filter are needed. Besise, signal outputs are acquieed by A/D conversion and send to the computer. Use mathematical morphology method to design a digital filter, filter the ECG interference. Finally, calculated the diaphragmatic EMG intensity and median frequency in the time domain and frequency domain, and the results will be applied to actual clinical treatment, including ventilator fan trigger control and fatigue diagnosis of diaphragm.