基于单片FPGA的多通道磁共振成像接收模块

An FPGA-Based Multi-Channel Receiver Module for Magnetic Resonance Imaging

提出了一种基于FPGA的多通道磁共振成像接收模块,能对多个独立通道的磁共振信号进行直接采样、数字下变频,以及数据流控制,并对其进行了成像实验.设计中采用Xil-inx公司的系统级DSP开发工具——System Generator对FPGA内部所有功能进行建模、仿真并生成相应的硬件描述语言.模块的采样速率为80MSPS,能灵活实现1kHz～1 MHz范围的可变接收带宽,适用于1T以下的磁共振成像系统;在单片FPGA内完成1～4个通道采样信号的数字正交解调,抽取滤波和数据流的处理,并可扩展至8通道.实验证明模块具有体积小,集成度高,可重构性强和成本低等特点,为磁共振成像谱仪的多通道接收系统提供了一种高性能的数字化解决方案.

A field programmable gate array （FPGA）-based multi-channel receiver module was developed for magnetic resonance imaging （MRI）, with its performance evaluated by MRI experiments. Based on a single FPGA, this apparatus operates direct sampling, digital down conversion and data flow control for multi-channel MR signals. The system level digital signal processing （DSP） development tools offered by Xilinx company System Generator was used for FPGA function modeling, simulation and automatic code generation of HDL. The sampling rate of this module is 80 MSPS and the receiver bandwidth can be varied between 1 kHz and 1 MHz, thus the module is suitable for an MRI system with a magnetic field lower than 1 T. Inside the FPGA, digital quadrature demodulation, decimation filtering and data stream processing of one to four channels of sampled signals are performed, and the module is expandable to 8 channels. This module has features of small size, highly integrated and reconfigurable and low cost, providing a high-performance digital solution for multi-channel reception system of an MRI spectrometer.