The ''harmonic oscillator'', introduced by Itzykson and Balian, is con
sidered, on finite phase-space lattices with the structure of Galois f
ields GF[p2]. We study this system at the classical and quantum mechan
ical level. Explicit construction of the quantum eigenstates provides
us with a detailed understanding of the spectrum of scales relevant to
this model. We construct also the coherent states appropriate to the
finite Heisenberg-Weyl and affine groups. Possible applications are di
scussed.