With the development of society, people's awareness of medical care has become stronger and stronger, so the training of doctors has become a very important link. Electrocardiography defibrillation technology is a major aspect of doctor training. If the operation is standard and the movement is proficient, it is often between emergency and rescue. If it can truly simulate the emergency defibrillation scene during training, it will Play a good learning effect. Therefore, in first aid and invasive clinical operation training, medical simulation teaching increasingly shows its advantages of low cost, high repeatability, high teaching efficiency, and compliance with medical ethical requirements. The defibrillation simulation generation system can choose any of 34 states (including adults and children), and can also connect a medical monitor to make the defibrillation simulation more realistic. Students can perform defibrillation exercises of different energies, which also makes it easy for teachers to check the learning effects of students. The system is developed based on the relevant principles of electrocardiogram and the signal synthesis principle of the monitor, strictly in accordance with the relevant medical regulations, and the generated waveform achieves the purpose of medical teaching. A more realistic effect is achieved at the key points of the relevant morbid ECG. After the system receives the high-pressure defibrillation signal, the corresponding waveform transformation is performed according to the system's preset settings. The system can be used as a training tool for medical training institutions to enable students to quickly master the method of ECG defibrillation. The system is used in conjunction with first aid simulators and monitors and has broad market prospects. The ECG defibrillation simulation generation system introduced in this paper takes ARM9 as the control core and makes full use of ARM9's rich I / O resources and powerful processing functions. It adopts an embedded development scheme, and comprehensively considers the versatility and usability of the system. The amplitude of the system output signal is 0 ~ 5 mV. It can continuously output ventricular and supraventricular premature beats models. It can also produce a cycle of 1 s. A square wave with a pulse width of 100 ms and an amplitude of 1 mV. It is easy to calibrate the monitor, and the signals are all output with three-lead synchronous signals. 1 System structure and design plan The system mainly includes ARM9 central processing unit, high voltage defibrillation signal acquisition module, D / A conversion module, signal matching module with monitor, ECG waveform simulation and data extraction, application program design and other parts. This system uses ARM9 embedded development platform. The following is the main structure and characteristics of ARM9 processor. (1) 32 b fixed-point RISC processor, improved ARM / Thumb code interleaving, enhanced multiplier design, and support for real-time (real-TIme) debugging; (2) On-chip instruction and data SRAM, and the memory capacity of instruction and data is adjustable; (3) The capacity of on-chip instruction and data cache (Cache) is from 4 KB to 1 MB: (4) Set a protection unit (ProtocTIon Unit), which is very suitable for segmenting and protecting memory in embedded applications; (5) AMBA AHB bus interface is used to provide a unified address and data bus for peripherals; (6) Support external coprocessor, simple handshake signaling support for instruction and data bus; (7) Support standard basic logic unit scanning test method; (8) Support BIST (Built-in-self-test); (9) Support embedded tracking macro unit, support real-time tracking instructions and data. The overall design of the ECG defibrillation simulation generation system is shown in Figure 1. 2 System hardware design This part is mainly divided into ARM9 hardware platform, D / A conversion, filter circuit, high-voltage defibrillation signal acquisition, the system hardware connection diagram is shown in Figure 2. Under the control of ARM9, the system converts the waveform data to analog quantity for output by D / A conversion. When the high-voltage acquisition signal is received, the processor will convert and output another ECG waveform. 2.1 D / A conversion and resistance attenuation network This part is the core of the system. In order to ensure the stability of the system and the requirements of the ECG signal, the D / A conversion chip uses an 8-bit parallel DAC0832 chip, which is powered by a single 12 V power supply. The provided data is transformed. The output part adopts 4th order Butterworth filtering. The output waveform is attenuated to obtain the required ECG signal. After active filtering, the peak value of the output waveform can reach 10 V, which is obtained through the resistor divider network 0 ～ 5 mV voltage output range. Considering the need to use three-way D / A, if each channel monopolizes 8 I / O ports, plus several control ports, the number of I / O ports provided by the processor is far from meeting the requirements, so it is planned to use a common data port, external The I / O port is chip-selected, which saves 16 I / O ports and also meets the requirements of signal output synchronization. Nantong Boxin Electronic Technology Co., Ltd. , https://www.bosencontrols.com
September 21, 2024