Software Defined Radio (SDR) and Direct Digital Synthesizer (DDS) for NMR/MRI Instruments at Low-Field

Abstract

A proof-of-concept of the use of a fully digital radiofrequency (RF) electronics for the design of dedicated Nuclear Magnetic Resonance (NMR) systems at low-field (0.1 T) is presented. This digital electronics is based on the use of three key elements: a Direct Digital Synthesizer (DDS) for pulse generation, a Software Defined Radio (SDR) for a digital receiving of NMR signals and a Digital Signal Processor (DSP) for system control and for the generation of the gradient signals (pulse programmer). The SDR includes a direct analog-to-digital conversion and a Digital Down Conversion (digital quadrature demodulation, decimation filtering, processing gain…). The various aspects of the concept and of the realization are addressed with some details. These include both hardware design and software considerations. One of the underlying ideas is to enable such NMR systems to “enjoy” from existing advanced technology that have been realized in other research areas, especially in telecommunication domain. Another goal is to make these systems easy to build and replicate so as to help research groups in realizing dedicated NMR desktops for a large palette of new applications. We also would like to give readers an idea of the current trends in this field. The performances of the developed electronics are discussed throughout the paper. First FID (Free Induction Decay) signals are also presented. Some development perspectives of our work in the area of low-field NMR/MRI will be finally addressed.

Rapid phenotyping towards personalized malaria medicine

“…The OPENCORE NMR project [39] by K. Takeda for example, has lowered the barrier of building NMR spectrometer tremendously. The emergence of software-defined-radio (SDR) [21,40,41] is making what once used to be expensive radio pulser/receiver within the reach of hobbyist now. SDR enables the replacement of traditional hardware of radio-frequency components with software-based signal processing.…”

Software Defined Radio SDR and Low Field Magnetic Resonance Imaging MRI -A Review

“…Channel enable (1)(2)(3)(4): Enable the TX channels, Channel 1 -TX1-I Channel 2 -TX1-Q Channel 3 -TX2-I Channel 4 -TX2-Q.…”

“…Moreover, the parameters of the system are fully programmable. They could be modified by the software and without changing the hardware Paul Yonnet, have resented the concepts of Software Defined Radio and Magnetic Resonance Imaging systems in their paper "Software Defined Radio (SDR) and Direct Digital Synthesizer (DDS) for NMR/MRI Instruments at Low-Field", sensors, 2013 [1].This paper mainly focuses on the fully digital radio frequency components for the design of MRI systems using low field. "Basics of Software Defined Radio and Application" by National Programme on Technology and Enhanced Learning (NPTEL) under Dr. Meenakshi Rawat, describes various co SDR's with the understanding of their limitation and application of Software Defined solutions in order to overcome such limitations [3].Dr.…”

A low‐cost multi‐channel software‐defined radio‐based NMR spectrometer and ultra‐affordable digital pulse programmer

“…In recent years, several publications have described the development of low-cost NMR systems (eg, [1][2][3][4][5], NMR systems built upon SDR devices, [6][7][8][9] and custom integrated circuits for NMR. [10][11][12][13] Many of these systems are limited to low-field use, and the vast majority have been single-frequency instruments.…”