A FPGA based radio frequency source and pulse programmer for NQR is described. With the use of direct digital synthesis (DDS), the RF source has the ability to yield RF signal with short switching time and high resolution in frequency and phase. To facilitate the generation of RF pulses, pulse programmer implemented in FPGA, is also used as auxiliary controller of DDS. The pulse programmer controls the DDS to generate RF pulses according to predefined parameters.
Hemnani, P., Rajarajan, A. K., Joshi, G., & Ravindranath, S. V. G. (2016). FPGA Based RF Pulse Generator for NQR/NMR Spectrometer. In Procedia Computer Science (Vol. 93, pp. 161–168). Elsevier B.V. https://doi.org/10.1016/j.procs.2016.07.196