  We have studied the spectral and timing behaviour of the atoll source 4U
1608-52. We find that the timing behaviour of 4U 1608-52 is almost identical to
that of the atoll sources 4U 0614+09 and 4U 1728-34. Recently Muno, Remillard &
Chakrabarty (2002) and Gierlinski & Done (2002) suggested that the atoll
sources trace out similar three-branch patterns as the Z sources. The timing
behaviour is not consistent with the idea that 4U 1608-52 traces out a
three-branched Z shape in the color-color diagram along which the timing
properties vary gradually.
