Design Of Multi-channel EP/EMG System And Research Of Signal Extraction Algorithm

Evoked potentials signal is neurological activity system of human body under external stimuli, which describe the human nervous system subjected to external stimulus presented the electrical characteristics of integrated in specific areas and specific time, is a kind of weak human electrophysiological signal; Electromyography, refers to the muscle in the static or contraction of the time when the electric activity, recording muscle potential activity curve called EMG; In particular, the acquisition of evoked potential extraction, provides a new method to the study of central nervous system, and now is become one of the most important tools for clinical diagnosis of modern neuroscience. It is by applied on human body of visual, auditory, or body sense stimulation, then generated on the corresponding body surface recording of human induced biological electric activities; evoked potential studies has important significance on the human nervous system, clinical diagnosis, medical and rehabilitation engineering, information transmission, it has become a research hotspot in related fields.The multi-channel EP/EMP acquisition system in this paper, use the weak signal amplification technology and multi-channel synchronous data acquisition technology, can collect the evoked potential (EP) signal accurately, consist of PC module, the main controller module and stimulation module, signal amplifying and conditioning module. Stimulator module can produce a checkerboard, LED flash stimulation, ticking sound and the plosive sound, then the way of human stimulation was applied and stimuli evoked potential signal by signal acquisition module signal conditioning module for amplification, the controller module through the high-speed A/D sampling on electrophysiological signals after collection, and then through the Ethernet, use TCP/IP communication protocol to send the data to the upper computer software, then use the PC software for real-time waveform display, measurement, information management and further analysis and processing.EP/EMG signal is in the complex environment and very easy to be overwhelmed by the interference of the external environment, and clinical acquisition process often exist lots of ambient noise, such as spontaneous brain electrical signal, EOG signals, ECG signals and so on. Therefore, this paper takes extraction algorithm research of visual and auditory evoked potentials. Based on the analysis of the advantages and disadvantages of the traditional averaging technique, and for the average superposition residual interference noise and the incubation period of disturbance, a based on the arc tangent function of the IIR filter overlapping average algorithm is proposed in this paper. The algorithm is used to test the data, and the test results show that the algorithm is practical and effective, and meets the requirements of clinical medical.