  Guided by the working hypothesis that the Schwabe cycle of solar activity is
synchronized by the 11.07 years alignment cycle of the tidally dominant planets
Venus, Earth and Jupiter, we reconsider the phase diagrams of sediment
accumulation rates in Lake Holzmaar, and of methanesulfonate (MSA) data in the
Greenland ice core GISP2, which are available for the period 10000-9000 cal.
BP. Since some half-cycle phase jumps appearing in the output signals are, very
likely, artifacts of applying a biologically substantiated transfer function,
the underlying solar input signal with a dominant 11.04 years periodicity can
be considered as mainly phase-coherent over the 1000 years period in the early
Holocene. For more recent times, we show that the re-introduction of a
hypothesized "lost cycle" at the beginning of the Dalton minimum would lead to
a real phase jump. Similarly, by analyzing various series of $^{14}$C and
$^{10}$Be data and comparing them with Schove's historical cycle maxima, we
support the existence of another "lost cycle" around 1565, also connected with
a real phase jump. Viewed synoptically, our results lend greater plausibility
to the starting hypothesis of a tidally synchronized solar cycle, which at
times can undergo phase jumps, although the competing explanation in terms of a
non-linear solar dynamo with increased coherence cannot be completely ruled
out.
