A theoretical investigation of the formation of the so-called single p
ulse NMR echo has been undertaken in the presence of both Larmor and R
abi frequency inhomogeneities. It is found that this echo phenomenon,
together with weaker, equally spaced secondary echoes, evolves from mu
ltiple-pulse excitation under certain constraints with respect to inte
rpulse time intervals compared with longitudinal and transverse relaxa
tion times. These transient coherences arise from a complex superposit
ion of oscillatory free induction decays, which extend further into th
e time domain because of cumulative dephasing within each pulse in a m
ultiple-pulse sequence. The effect is present for large Larmor inhomog
eneity in isolation, but is stronger in the simultaneous presence of b
oth frequency inhomogeneities, characteristic of ferromagnets. Predict
ions of this model analysis are confirmed through experiment via conve
ntional, zero-field, pulsed NMR on binary (VFe)-V-51 and pure elementa
ry (enriched) (FeFe)-Fe-57 ferromagnets.