quadrature detection

in nuclear magnetic resonance spectroscopy
https://doi.org/10.1351/goldbook.08399
Collection of time domain nuclear magnetic resonance spectroscopy data on both the x and y axes of the rotating frame of reference to allow discrimination of positive and negative frequencies.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 701 [Terms] [Paper]