Synchronization without correlation

We present an experimental study of N unidirectionally coupled
Mackey-Glass electronic circuits with time delay in a ring configuration.
When the output of the ring is sent to a chain of N/2 oscillators, identical
synchronization is observed between pairs of corresponding elements in the
ring and chain. The novelty of the presented proposal resides on the fact
that distant elements in the ring and the chain can synchronize via an
uncorrelated signal generated by a mediator element. For the sake of
completeness, we also present numerical results with rings of several numbers
of oscillators and provide a possible application for chaos key
distribution.