一种基于CORDIC的磁共振射频脉冲发生器设计
收稿日期: 2025-10-10
网络出版日期: 2025-12-22
基金资助
国家自然科学基金资助项目(61101174);上海介入医疗器械工程技术研究中心项目(18DZ2250900)
A Design of CORDIC-based Magnetic Resonance RF Pulse Generator
Received date: 2025-10-10
Online published: 2025-12-22
核磁共振(Nuclear Magnetic Resonance,NMR)射频脉冲发生器对成像质量至关重要. 传统的直接数字频率合成技术(Direct Digital Synthesizer,DDS)要想实现较高精度则需要依赖大容量查找表,因此会占用较多的片上随机块存储器(Block Random Access Memory,BRAM)资源且灵活度受限. 本文提出一种基于坐标旋转数字计算机(Coordinate Rotation Digital Computer,CORDIC)算法的磁共振射频脉冲发生器设计,通过在现场可编程门阵列(Field-Programmable Gate Array,FPGA)中构建自定义CORDIC核实现射频信号的频率、相位和幅度的数字化调制,结合Zynq-7000全可编程片上系统(System on Chip,SoC)实现高集成度、低功耗的硬件架构. 实验结果表明,所设计脉冲发生器可输出频率分辨率为0.046 Hz、相位分辨率为0.005 5˚的射频脉冲信号,且四通道所占用的BRAM资源较传统DDS方案降低约21.4%. 该设计为NMR设备的射频前端小型化与高性能化提供了可行方案.
关键词: 核磁共振; 坐标旋转数字计算机(CORDIC); 射频脉冲发生器; 片上随机块存储器(BRAM)
刘颖 , 卢志豪 , 吕海龙 , 章浩伟 . 一种基于CORDIC的磁共振射频脉冲发生器设计[J]. 波谱学杂志, 2026 , 43(1) : 16 -26 . DOI: 10.11938/cjmr20253183
In nuclear magnetic resonance (NMR) systems, the radio frequency (RF) pulse generator critically influences imaging quality. Traditional direct digital synthesis (DDS) techniques rely on large-capacity lookup tables to achieve high precision, which results in excessive consumption of on-chip block random access memory (BRAM) resources and limits flexibility. This study presents a novel RF pulse generator design based on the coordinate rotation digital computer (CORDIC) algorithm. By integrating a custom CORDIC core within a field-programmable gate array (FPGA), the proposed system achieves digital modulation of RF signal’s frequency, phase, and amplitude. Combined with a Zynq-7000 system-on-chip (SoC), this design delivers a highly integrated and low-power hardware architecture. Experimental results demonstrate that the generator can output RF pulses with a frequency resolution of 0.046 Hz and a phase resolution of 0.005 5˚, while reducing BRAM resources occupied by four channels by approximately 21.4% compared to the traditional DDS solution. This design offers a feasible solution for achieving miniaturization and high performance in the RF front-end of NMR instruments.
Key words: NMR; CORDIC; radio frequency pulse generator; BRAM
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