A High Precision EEG Acquisition System Based on the CompactPCI Platform

Electroencephalography (EEG) is the recording of electrical activities generated by nerve cells in the cerebral cortex. As the only non-invasive method for measuring brain activities from human scalp, it has been widely used in the area of medical diagnosis, neuroscience research, commercial application, etc. Most of the existing EEG acquisition systems, which are usually comprised of analog switches, operational amplifiers, analog-digital converters and specific instruments, have the weakness of high expenses, limited accuracy and difficult to update. Aiming at the need of cognitive science research and brain computer interface (BCI) design, a high precision EEG acquisition system based on the compact peripheral component interconnect (CompactPCI) platform was designed in this paper. A commercial EEG hat with adjustable electrodes was used to collect interested EEG signals. And ADS1299, a high resolution analogy front end IC proposed by Texas Instruments, was adopted in the system to acquire and convert EEG signals. To facilitate hardware expansion, system integration and data processing, the device was designed in the form of a 3U CompactPCI card and connected to an embedded computer. A graphical user interface (GUI) software was provided to control the data acquiring, storing and processing. In addition, the least mean squares (LMS) adaptive filter was realized to optimize the signals. The compact and highly integrated analogy circuit in this design significantly avoided the contamination of signals by environmental noises and reduced device-to-device connection complexity. Meanwhile, the system structure based on the CompactPCI platform made it easier to adjust signal channels and evaluate novel algorithms. The accuracy tests and alpha wave detection experiments showed that our EEG acquisition system had high accuracy and was applicable to various EEG-related experiments. The research in this paper may have reference value for the development of portable EEG acquisition system and BCI device.