Modular PC-based data acquisition and processing system for biological signals

The data acquisition system described here is designed for biomedical resea rch and permits the recording of up to eight biological signals simultaneou sly. A personal computer using the Windows 95 operating system is employed for data monitoring, data processing and analysis during experiments. The s ystem has been designed for reliability, economy, flexibility and ease of h andling, with the aim of achieving universal application. To avoid interface incompatibility, problems with transfer protocols and th e data formats of commercially available products, analog signals are used for further processing. The individual input channels are electrically isol ated from one another and the PC to avoid ground loops, and for reasons of safety. An isolated voltage supply is available for pre-amplifiers and brid ges. A bandwidth of 0-5 kHz and the maximum sampling rate of 12.5 kHz suffi ce to pick up higher frequency signals such as EMG and ENG. The modular software and hardware concepts permit the use of almost any des ktop or laptop PC as a central processing unit. The PC handles documentatio n, data acquisition, data analysis and the preparation of publications. If needed, further analytical functions can be added in modular form. Finally, the option of saving data in the ASCII format permits processing of result s with such standard software packages as Excel, Access, Matlab and Origin.