An All-Digital High Precision Receiving Algorithm Based on General Floating Point DSP for Low-field MRI
基于DSP的全数字低场MRI信号接收算法研究

Receiver plays an extremely important role in a magnetic resonance imaging system as it's precision and stability directly determine the qualities of the images obtained. In this study, an all-digital receiving algorithm based on general floating point DSP was developed for low-field MRI systems, and shown to be highly precise and efficient. Amplified echo signal was first directly digitalized, and then sent to DSP where digital quadrature demodulation, filtering and decimation were carried out. Cascaded data filtering was done with filters with high computational efficiency including integrator-comb filter (CIC), half band filter (HB) and equiripple FIR filter. Single precision floating point format was used in the whole process so that high precision and large dynamic range were maintained. The algorithm developed was implemented with a DSP program in ANSI C and inline assembler. Simulation on CCS2.2 proved that it can be used for real time detection and meets the requirements for practical use.