In this case, the 1H FID is sampled during windows of the multiple pulse decoupling scheme where pulses are not being delivered, however the attainable resolution is still much less that that observed for liquids where the rapid molecular tumbling reduces the homonuclear dipolar interaction to zero.
The combined use of MAS and multiple pulse decoupling schemes (CRAMPS) can be used to improve the resolution. Solid-state 1H MAS NMR spectra with resolution comparable to that obtained for liquids, are difficult (if not impossible) to obtain. The main problem is that magic angle spinning is unable to average the homonuclear 1H dipolar coupling interaction to zero.
