32 Leads EEG Amplifier Design

The brain is the most complex and important organs of our body. Even to now, the brain is still a black hole of human cognition. With the development of "the brain project" in the whole world, the study of brain function is to a climax. Electroencephalography(EEG), which is an important tool in the study of brain, has become an important tool for brain research because of its advantages such as no damage, low cost, easy acquisition and high time resolution.With the constant depth of brain function research, it’s required that the acquisition system obtain more EEG information in the process of collecting EEG. On the one hand, the EEG data generated by the EEG acquisition process is increasing, which is a new challenge for design of acquisition system structure and ability of processing data in the system; On the other hand, there is a new discovery on the frequency species of EEG signals, so the traditional domestic acquisition system cannot satisfy the requirements of the acquisition bandwidth. In addition, the EEG signal is microvolt signal, vulnerable to noise acquisition. The ability of anti-interference and noise suppression of EEG also needs attention.At present, the performance of EEG acquisition system in China is relatively backward compared with the foreign equipment. Domestic brain science research field is relatively dependent on foreign equipment. High performance EEG acquisition system development with independent intellectual property rights is of far-reaching significance to the sustainable development of domestic research on brain function.In order to improve the performance of the domestic EEG amplifier, the 32 leads amplifier is designed and developed. The 32 leads EEG amplifier adopts the board structure, which comprises four acquisition boards of eight leads and a main control board. The design can facilitate the control of the leads, in the solution of the design of the system, it can provide a simple method to design more leads EEG amplifier. Acquisition board refers to the traditional amplifying, filtering and modulus conversion circuit, at the same time, we design the data buffer circuit to solve the problem of large amount of data. The introduction of the buffer circuit can effectively improve the sampling rate and the total number of leads of the traditional EEG amplifier. The main control board, including DSP and USB circuit, is mainly responsible for the integration of data and data upload to the host computer.Through the performance test of the collection system, some key performance indexes of the system are significantly improved compared with the domestic similar products. The system has high stability and reliability in the process of actual EEG acquisition and related EEG experiments.