Introduction and overview

Modern NMR or MRI receivers are implemented digitally resulting in superior performance and more compact solutions. The first digital receiver implementations were based on dedicated integrated circuits but today most designs are now based on Field Programmable Gate Arrays (FPGA) as they provide sufficient performance as well as flexibility.

This educational session will start by reviewing the past and then quickly move into describing some of the steps and tools that people can use to design and build their own digital receivers. The key topics covered will be the digital signal processing chain, graphical FPGA circuit design using custom and free IP and the key signal processing IP blocks such as the Cascaded Integrator Comb low pass decimating filter.

Time will then be spent addressing the topic of high-performance sampling where simultaneous subsampling and oversampling is performed to achieve high dynamic range at input frequencies of several hundred MHz. The roles of low phase noise clocking and decimating low pass filters will be explained.

Finally, three different hardware implementations will be presented as options for developers to adopt. These range from a complete prebuilt but closed solution to a custom “roll your own” approach that uses available open source FPGA modules to speed up and simplify the development.

Acknowledgements

No acknowledgement found.