Adesign Of Magnetic Resonance Imaging Spectrometer Of Sequence Controller Based On DSP

With the increasing application of magnetic resonance imaging(MRI)technology, people desire high performance MRI system. Spectrometer isthe core device of MRI system, which performance is critical to theimaging performance of MRI system. As the control unit of thespectrometer, sequence controller determines the operation mode ofimaging sequence and control mode of every functional module, which isthe key point of spectrometer design. With the development of digitaltechnology, especially the promotion of digital signal processor (DSP)chips, therefore the design of a sequence controller for high performanceMRI spectrometer has excellent basis.In this subject, a sequence controller based on DSP(TMS320VC5509A) is developed, each of which basic function has beenverified, including the control over RF generation, gradient generation,and echo receiving. Such sequence controller takes DSP and FPGA ascontrol core, has relatively ample hardware resources, and its operationresolution is10ns. Such configurations can support the high-speedexecution of imaging sequence conveniently; implement the accuratecontrol over each function of the spectrometer, so as to make an excellent basis for the developing next generation spectrometer which ishigh-performance, compact, and low-cost.The main tasks implemented in this subject are listed below:(1) Hardware design and manufacture of the sequence controller,the test of each function, including the Bootloader and USBcommunication of the DSP;(2) Achieving the control of RF generated module, under settingparameters and certain timing requirements, sequence controller cancontrol the RF generated module to generate hard pulse and soft pulse.(3) Achieving the control of gradient generated module, undersetting parameters and the timing requirement, sequence controller cancontrol the gradient module to generate the pre-emphasized gradientsignal in X、Y and Z direction.(4) Achieving the control of data acquisition module, undersetting parameters, therefore implement data acquisition and digitaldemodulation.