Abstract: Combination of digital quadrature detection and over-sampling techniques is discussed in detail. It is demonstrated by theoretical analysis and experimental result that, through simultaneous changes of sampling frequency and the frequency difference between radio-frequency irradiation and reference signals, one can complete the NMR data processing procedure with performing digital filtration once. As a result, the whole data processing procedure may, in most cases, be accomplished within the time interval waiting for the recovery of the magnetization.

Key words: Digital quadrature detection, Over-sampling, Data processing