Zero-quantum suppression in NOESY and experiments with a z filter

A refined procedure for the suppression of undesired coherences by averaging of experiments recorded with equidistant incrementation of a filter delay is described. A detailed analysis for the suppression of zero-quantum coherences in NOESY, ROESY, and experiments with a z filter is carried out. Plots which allow a rapid estimate of the degree of zero-quantum suppression as a function of the number of experiments performed with different delays are devised. Averaging over a maximum number of different filter delays is achieved by the use of two-step CYCLOPS which shortens the phase cycle of each individual experiment.