在核四极矩共振（NQR）领域，射频激励脉冲信号的优劣对NQR响应信号有重要影响.针对常规方法中射频激励脉冲参数不可控的问题，本文基于32位闪存微型控制器STM32和直接数字频率合成（DDS）芯片AD9910设计了一种相位可控激励脉冲发生器.采用STM32控制AD9910产生波形参数（脉冲宽度、脉冲间隔、脉冲个数和共振频率等）可控的射频激励脉冲，利用LabVIEW软件平台设计脉冲参数设置界面，并建立计算机与微控制器通信，实现波形参数的精确优化控制.实验结果表明，该方法实现了相位可控的NQR激励脉冲序列，可为后续NQR信号检测提供有效激励源.
The quality of the radio frequency (RF) excitation pulse signal has important effects on nuclear quadrupole resonance (NQR) response signal. In this work, a phase-controllable excitation pulse generator was designed based on the 32-bit flash microcontroller STM32 and the direct digital frequency synthesis (DDS) chip AD9910. STM32 is used to control the AD9910 to generate RF excitation pulses with controllable carrier phase. The LabVIEW software platform was used to design the pulse parameter setting interface, and the computer and microcontroller were established to communicate. This design achieved precise and optimized control of the waveform parameters (i.e., pulse width, pulse interval, number of pulses and resonance frequency) for the RF pulse. Experimental results demonstrated that this method could be used to obtain a phase-controlled NQR excitation pulse sequence, providing an effective excitation source for subsequent NQR signal detection.
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