Abstract: The design of an integrated NMR spectrometer based on USB is introduced. The spectrometer, in which the control/communication unit, pulse generator, RF waveform transmitter and digital receiver are integrated onto one card, can works in two modes. In Mode I, the spectrometer communicates with a PC through USB connection, and is controlled by PC to complete all tasks including real time control of the spectrometer and data display/processing. In Mode II, the spectrometer is controlled by an integrated microprocessor and can complete all tasks without the participation of the PC. The performance of the proposed system was tested in three experiments using single-pulse, spin-echo and CPMG pulse sequences, respectively.

Key words: nuclear magnetic resonance, integration, USB, microprocessor unit