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

In recent years, a new generation of software-defined radio (SDR) products has emerged that are well suited for adaptation for NMR instrumentation. The software and hardware of a new NMR spectrometer console based upon an inexpensive SDR product are described. This device is provided with open-source firmware and drivers which have allowed the customization of its behavior and optimization for use in NMR. In particular, these low-level modifications have allowed for straightforward synchronization of multiple SDR boards with each other and with other devices. Control of other devices is facilitated by a new digital pulse programmer constructed using an inexpensive open-source, widely available microcontroller platform. The strategy used for precise, reproducible synchronization of the different components is described in detail. Representative spectra are presented demonstrating both high-resolution and wide-line spectroscopy with spectral widths up to 50MHz.