Compounds that inhibit Aurora-kinases, compositions containing the compounds and methods of treating diseases using the compounds are disclosed. The lock detector is configured to generate a lock signal based on control signals of a phase lock loop circuit that generates an output clock of a desired frequency that is phase locked to a reference clock. The correlative component in the primary signal is minimized by applying an adaptive filter to the reference signal and subtracting the filtered reference signal from the primary signal to produce a residue signal, wherein the coefficients for the adaptive filter are selected to minimize the least square error of the residue signal.