Modular Multi-channel Real-time Bio-signal Acquisition System

Abstract

Here, we present a multi-channel data acquisition system designed to record bio-electrical signals. The hardware concept is modularand consists of front-end acquisition modules and a synchronization module. The raw data streams are analyzed and stored on a personal computer or a single-board computer, which enables complex decisions and control algorithms even in real-time applications.

The system is capable of combining up to eight front-end acquisition modules, each using a separated universal serial bus data-link to the computer. Therefore, it is important to ensure a reliable synchronization of all acquired signals. Hence, the modules are synchronized by an external clock module, which provides the time-base for the microcontrollers and generates repetitive trigger pulses. The developed system ensures a synchronization error smaller than 10 μs which meets the requirements for real-time analysis of movements. The analog front-end circuit is based on the high integrated chip ADS1299 (Texas Instruments Inc., Dallas, TX, USA), which incorporates analog filters and simultaneous digitalization of eight bipolar channels. The hardware is designed to suit transcutaneous recording of bio-electrical signals, like electromyogram, electrocardiogram, and electroencephalogram. Nevertheless, the device is also capable of acquiring sensor and other bioelectrical signals.

The advantage of the system is a flexible design which supports real-time recordings up to 64 bipolar channels. The modular design reduces the front-end complexity and enables simple integration in complex acquisition systems.