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The voltage noise of a Bi2Sr2CaCu2O8+x single crystal below Tcis analyzed with an asymptotic power spectrum method. Low-frequency noise power Sv(T) shows a peak at T = Tp. Above Tp, the power spectrum, Sv(f), exhibits a power-law fall-off. Below Tp, Sv() dramatically deviates from the power-law behaviour, showing some wide peaks which are proposed upon a background of an exponential-law characteristic. This is qualitatively consistent with numerical simulation. It is suggested that the pinned vortex state is a deterministic motion with low-dimensional chaotic attractors while the unpinned state is an extended dissipative dynamic system with self-organized criticality.