  The resolution of separation of two elementary signals forming a partially
coherent superposition, defined by quantum Fisher information and normalised
with respect to detection probabilities, is always limited by the resolution of
incoherent mixtures. However, when the partially coherent superpositions are
prepared in a controlled way the precision can be enhanced by up to several
orders of magnitude above this limit. Coherence also allows the sorting of
information about various parameters into distinct channels as demonstrated by
parameter of separation linked with the anti-phase superposition and the
centroid position linked with the in-phase superposition.
