A low‐cost NMR spectrometer
A low‐cost multi‐channel software‐defined radio‐based NMR spectrometer and ultra affordable digital pulse programmer
The LimeSDR14¹ is a small (12 × 7 cm), USB3 interfaced circuit board capable of rf transmit and receive over a frequency range of 100 kHz to 3.8 GHz. Both transmit and receive channels are equipped with programmable‐gain amplifiers and sophisticated digital signal processing modules, allowing the board to function as a nearly complete NMR spectrometer console.
The hybrid analog/digital nature of the rf on this device allows for elimination of the artifacts associated with analog rf systems while simultaneously covering the full range of relevant frequencies.
The open‐source nature of the software and firmware supporting the device has allowed a number of modifications to be made to allow predictable timing of multiple devices to nanosecond precision.
A key feature of the present work is the development of the synchronization mechanisms needed to reproducibly synchronize multiple rf channels with each other, and with externally produced logic signals.
This project is a flexible, expandable, multi‐channel transmit/receive console for NMR based upon an inexpensive, open‐source software‐defined radio platform and Arduino Due‐based pulse programmer.
 LimeSDR Crowd Supply Homepage. https://www.crowdsupply.com/lime-micro/limesdr. Accessed June 4, 2018
1Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada