States-TPPI
From NMR Wiki
States-TPPI technique achieves two effects for a given indirect dimension (say, dimension F1): (1) signal frequency discrimination and (2) displacement of the unmodulated artefact signal from an inconvenient location in the middle of spectrum to the edge.
(1) is achieved by recording two data sets at each t1 point - one with the phase of preparation pulse of x and one with phase y and storing those data sets in separate locations.
(2) - by inverting phase of preparation pulse and receiver each time when t1 is incremented. The result of this is that artefact signal at F1=0 Hz appears at F1=±SW/2 Hz
The data is subsequently processed by the complex Fourier transformation, real part of which is used for the subsequent analysis.
Reference
Marion, D., Ikura, M., Tschudin, R., Bax, A.. Rapid recording of 2D NMR spectra without phase cycling. Application to the study of hydrogen exchange in proteins
