  We have found a synchronization behavior between two identical chaotic
systems^M when their delay times are modulated by a common irregular signal. ^M
  This phenomenon is demonstrated both in two identical chaotic maps whose
delay times are driven by a common^M chaotic or random signal and in two
identical chaotic oscillators whose delay times are driven by^M a signal of
another chaotic oscillator. We analyze the phenomenon by using^M the Lyapunov
exponents and discuss it in relation with generalized synchronization.^M
