This paper investigates dynamical systems arising from the action by t
ranslations on the orbit closures of self-similar and self-affine tili
ngs of R-d. Th, main focus is on spectral properties of such systems w
hich are shown to be uniquely ergodic. We establish criteria for weak
mixing and pure discrete spectrum for wide classes of such systems. Th
ey are applied to a number of examples which include tilings with poly
gonal and fractal tile boundaries; systems with pure discrete, continu
ous and mixed spectrum.