A Phase-Controllable Nuclear Quadrupole Resonance Excitation Pulse Generator

Abstract

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.

Keywords

• nuclear quadrupole resonance (nqr)
• phase-controllable excitation pulse
• direct digital frequency synthesis (dds)
• stm32