基于任意波形发生器的原理,采用ddS(dIrECT dIgITAl SynTHESIS)技术,以单片机控制芯片STC89lE51和fPgA芯片XC5VfX70T为基础进行硬件和逻辑设计,使用ISE10.1和MOdElSIM软件编写脉冲波形发生器的各个子模块和测试模块,利用上位机软件或者键盘模块进行设置,改变波形频率和相位,最终产生核磁共振谱仪所需的调频调相波形数据。仿真结果表明,该方案产生的信号波形可灵活实现频率和相位的更改,波形性能良好,对于核磁共振谱仪发射脉冲波形的设计提供了可靠的方法和思路。The hardware and logic design based on MCU control chip STC89LE51 and FPGA chip XC5VFX70T combines the principle of the arbitrary waveform generator with DDS(direct digital synthesis) technology.The sub-modules of pulse waveform generator and test modules are designed by ISE10.1 and Modelsim.Using the PC software or keyboard to set the frequency and phase of waveform,the ultimate frequency modulation and phase modulation waveforms data required by the NMR spectrometer can be generated.The simulation results show that the signal waveform designed by the program can have a good performance in the change of frequency and phase,providing reliable methods and ideas for the design of the transmit pulse waveform in the NMR spectrometer.国家自然科学基金(11175149)资助项
