Multiphase Digital Synthesis of RF Signals Based on FPGA High Field MRI-EPT Spectrometer

Magnetic resonance imaging (MRI) plays a crucial role in clinical diagnostic imaging. It is based on the physical principles of nuclear magnetic resonance, generates a radio frequency field by utilizing radio frequency excitation signals, excites hydrogen protons in biological tissues to generate Larmor precession in the magnetic field, and then processes the echo signals to obtain magnetic resonance images to reflect the characteristics of biological tissues. The higher the magnetic field intensity, the higher the spatial resolution of magnetic resonance imaging, and the frequency of RF excitation signal needs to be improved synchronously. In order to generate the radio frequency(RF) excitation signal of ultra-high field magnetic resonance, and realize the high-integration RF excitation signal system based on field-programmable gate array(FPGA), this paper adopts the method of multiphase synthesis, and combines with digital-to-analog converter (DAC) module to realize the output of 400 MHz magnetic resonance Sinc RF pulse signal, and the signal sampling rate is as high as 2 GSPS, which meets the requirements of magnetic resonance imaging under 9.4T magnetic field.