Design And Implementation Of Preamplifier System For High-field NMR Spectrometers

NMR instrument technology has been paid more attention with NMR technology being widely used. Preamplifier system plays a critical role of the entire spectrometer, and even the whole NMR spectrometer will be affected by its performance.This subject aims at designing a preamplifier system which consists of a main controller, a broadband preamplifier, a high band preamplifier, a lock preamplifier and a mixer.The development history of NMR spectrometer, progress and status of domestic and foreign are discussed in this essay. The structure of the NMR spectrometer was general introduced, departure from the actual experimental process.Detailed design of preamplifier system and system testing were presented.The main research contents are as follows:1) The design index of preamplifier system was specified, according to the NMR experiment, and overall design of preamplifier system was designed.2) A controller based on CAN bus was proposed.3) Preamplifiers with RF switch, filter and low noise amplifier were designed.4) A quadrature mixer was constructed.5) Some electrical performance tests and NMR experiments results were intended to verify the feasibility of the system.