Digital Development And Application Of Multi-lead Physiological Recorder

Multi-lead Physiological Recorder is an experimental instrument which can simultaneously record multiple physiological parameters, and it can collect physiological signals by sensors. After processed by experimental modules, these signals are converted into electrical signals and outputted by the amplifier and then recorded in the form of physiological curves depicted in the graph paper [1]. Multi-lead physiological recorder is a common device in the study of experimental medicine and clinical medicine. It has important significance for understanding the physiological and pathological changes of the disease and the effect of drugs.The center of functional experiment has five RM-6000 Multi-lead physiological recorders, purchased in the 1980 s, and is worth more than a million. The instrument is mainly composed of the host, oscilloscope, and recorder composition. It can observe and record more physiological parameters by oscilloscope and recorder at the same time. Meanwhile, it can also record the pressure, EEG, ECG, EMG, respiration, pulse and other physiological signals. For years, it plays an important role in teaching and research work. Due to it, there are about 600 students benefiting from it each semester and hundreds of paper on scientific research teaching and student independent design is published.The old multi-lead physiological recorder does not record for a long time and the recording pen is easily damaged. Moreover, recording paper cannot be long-term preservation and it only records but not analyze. Thus, it cannot meet the need of modern experiment teaching. And even some companies have no longer produced the old parts for the old multi-lead physiological recorder, so the broken recorder cannot be improved timely and thus this instrument has been in end-of-life stage [2]. Here, we use a large scale integrated circuit and computer hardware and software technology to develop a computer instrument which has biological signal display, processing, storage, and analysis for the experimental teaching. This project has some characteristics as follows:(1) to make the old multi-channel physiological recorder digitalization.(2) to save a lot of recording paper and pen(3) to make electrophysiological signal convert into digital signals, increasing the stability and reliability in the whole.(4) to provide a kind of menu operation which is easy to operate and communicate. Our Innovation is that the project can make the old polygraph modernization. In case of cancellation of record paper, it may record, storage and display, and be able to analyze and print various physiological signals. After reconstructing, it can replace the recorder and the oscilloscope. The new multi-lead physiological recorder can save millions of funds and be widely used in teaching, physiological, pharmacological and pathological physiology experimental biological signal detection, collection and analysis of the hardware of the system.The project mainly consists of two parts: hardware design and software design.Hardware designLevel conversion circuit: the output voltage of multi-lead physiological recorder ranges from plus ten volts to minus ten volts, but we use low power MSP430 series of signal acquisition, and the input voltage ranges from 0 to 3.6 volts. Therefore, we need a level conversion circuit and a voltage lifting circuit.A/D sampling circuit: the output voltage of the multi-lead physiological recorder is an analog signal, but the computer can only deal with digital signals, and thus we use low power microcontroller MSP430 series make A/D conversion.The central control circuit: we employ low power MSP430 MCU control in the whole, including the keyboard input circuit, output display circuit, communication circuit and microcomputer.The computer interface circuit: The MCU MSP430 communicated with the microcomputer through the RS232 asynchronous communication mode.Software designHardware driver software: we use the low power MSP430 MCU as the control center in the whole, and the software is realized by the C language. A variety of hardware driver software includes the keyboard input driver, the display output driver, and the computer communication driver et al.A/D sampling software: A/D conversion software uses the timing interrupt mode to control the interval of sampling time, which ensures the interval. The software is realized by the C language.The storage and display software of computer: The computer software is realized by the VB language, including a main control window interface procedures, a computer communication program, a microcomputer data display program, a computer storage and handling procedures.