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在功能磁共振实验设计中,需要利用脉冲发生器模拟磁共振设备的扫描脉冲以实现精确的时间控制。本文提出了一种基于单片机PIC16F877的MRI仿真低频脉冲发生器设计方案,用于需要精准时序的功能磁共振实验设计。本装置的核心部分是单片机PIC16F877,通过单片机的软件来产生不同频率和占空比的脉冲波。通过选择开关来实现脉冲周期和占空比的调节;同时用数码管LED显示脉冲的相应周期。由此装置得到的脉冲幅度为5V,可调周期范围是0.5s~8.0s,精度为0.1s。占空比有20%、30%、40%、50%4种可调。这种MRI仿真脉冲发生器使用简单方便,产生的低频脉冲精度高并且稳定性好,能很好的模拟功能磁共振实验中需要的脉冲信号。
In functional MRI experiments, a pulse generator is needed to simulate the scan pulse of a magnetic resonance device for precise time control. This paper presents a PIC16F877 microcontroller-based simulation of low-frequency pulsed MRI pulse generator design for accurate timing required functional magnetic resonance experimental design. The core part of the device is the PIC16F877 microcontroller, through the microcontroller software to generate different frequency and duty cycle pulse wave. By selecting the switch to achieve the pulse cycle and duty cycle adjustment; the same time with digital LED display pulse corresponding period. The pulse amplitude obtained by this device is 5V, the adjustable period range is 0.5s ~ 8.0s and the accuracy is 0.1s. Duty ratio of 20%, 30%, 40%, 50% 4 adjustable. The MRI simulation pulse generator is simple and convenient to use. The generated low frequency pulse has high precision and good stability, and can well simulate the pulse signal required in the functional magnetic resonance experiment.