Biomedical Signal Data Acquisition System

The acquisition and processing of biomedical signals is an important branch of the Biomedical Engineering, it provides the essential data for basic research and clinical diagnosis , analysis of Biomedical Engineering. In order to meet the demands of teaching and scientific research, it is necessary to carry on the research and design about acquisition and processing system of biomedical signals.According to the characters of biomedical signals, this paper designed a kind of acquisition and processing system of biomedical signals that can totally replace conventional experiment instruments such as oscillograph, recorder, stimulator, and amplifier. The system combines the advantages of conventional instruments and the powerful processing function of computer.The acquisition and processing system of biomedical signals is composed of two parts: hardware and software. The hardware part mainly deals with the acquisition of all kinds of biomedical signals and the conditioning, amplifying, A/D converting which are imposed on the signals, only after this can the signals enter the computer, while the software part displays, records, processes the acquired signals and controls other parts of the system. The author mainly takes charge of hardware design of the system. In the design, takes the methods of designing signal amplifier and signal acquisition on different circuit boards. This design method deals with analog signals and digital signals separately which satisfies the request of digital instruments design, and resolves the problem of cross-interference between analog signals and digital signals, so the anti-interference ability of the system is greatly improved.In this dissertation, the author mainly undertakes the design of the data acquisition circuit board for biomedical signals. The main design work as follow: four biomedical analog signals input channels' design; the design of AT89C51 Microprocessor system which can change the sampling rate; the DMA interfacing circuit design by which the sampling data enter the computer; the interfacing circuit design between PC and signal amplifier, and the reliability and anti-interference design of this system, etc.