MIT-BIH Physiological Signal Management And Playback System

In recent years, the progress of the modern electronic technology and the rapid development of digital computer technology greatly promoted to the depth of the ecg information research. Especially come out the DSP, ARM and other advanced processing unit, ventricular wave identification detection, T-wave alternate detection theory of algorithm is more perfect, and the more cause is the need of the people to cherish themselves life, crying for an advanced, practical and convenient remote ECG monitoring instrument as soon as possible appearance.MIT-BIH physiologic management and playback system is the important part of the remote ECG monitoring instrument. This system carry through the management and playback about the data of the MIT-BIH main ECG data including few other database, and to constructe the platform about experimental data, that can be use to produce simulate physiological singal about cardiogram and breath, subsequently use the singal to debug the remote ECG monitoring instrument.During the design of the platform, firstly, the article introduces three international common ecg databases and the ones that are used by this project. laterly, the read method of the physiological database is also done including the read of the header files, data files and notes files etc.The files name, numbers of channel, numbers of sampling, the resolution ADC sampling points, and the ADC zero, checkout numbers and lead are detailed instructioned in the read of the header files. Reading the data files, The hexadecimal display file(fragments) introduces the data storage, we can get real amplitude; Reading the annotations file, to determine the annotations file format is MIT or AHA format,to simply introduce the content of the MIT format. Understanding the database is the foundation of D/A synchronous playback and screen retrieval.Secondly, the article introduces design of hardware and software platform of replay system in detail. In the hardware structures, considering the characteristics of ecg signals stored in real-time, the requirement of real-time playback of hardware, software development tools etc. comprehensive factors, we select MP411 card which based on USB2.0 to achieve DA conversion finally ; Then the article introduces the principle diagram of MP411, Microcontroller CY7C68013, DAC7613; On the part of D/A principle , the article introduce some operation function which is used to realize DA conversion function; Finally the performance index on D/A module is introduced also. Software platform design based on MFC of visual c++ is divided into three main modules, including: database management module, the D/A replay module, screen retrieval function module. Database management module is responsible for some basic file operations ,such as opening the file,closing the file etc, to database and storage of data files after retrieval, converts data of these databases into uniform one in memory which will be used by other modules. About D/A replay module, the article introduces respectively its function of waveform display on screen and D/A synchronous playback, and their realizing process and key algorithms; Through replayed two waveforms, The author analyzed screen waveform and playback waveform, proved the two signals synchronism and that D/A replay amplitude equal to theory one. About function module of retrieving on screen, the article mainly introduces the process of waveform retrieval and the one of storage with uniform format of retrieved signals.Finally, the article elaborates key technology of using in the software platform, including calling dynamical link library technique,microsecond delay technique,multithread technique,synchronous communication mechanism,double buffering graphics technique etc, and describing the application of these technologies in this system. On the DLL technical description, author introduces the characteristics and using methods of calling static and dynamic link library; Author introduces microsecond delay technique and its application in this project; It is introduced for the advantages and characteristics of multithread technique and the step of creating multithread in the project and how to realize D/A replay using thread function; It is introduced for five kinds of thread synchronization communication mechanism briefly and realized for thread synchronization using global variables technique; It is introduced for double buffering technique including double buffer, double buffer drawing Finally and for how to overcome of the drawing flashing problem using double buffer drawing. The application of these key technologies ensure a stable and efficient operation of the platform.At MIT-BIH physiologic management and playback system platform, the function of each module of get a very good. Through the platform control, different kinds of ecg signal after DA conversion can be directly applied to the test of remote ecg monitoring instrument prototype.