Patent ID: 7602445

Claim:
A clock reproducing device for reproducing an audio clock from a reference clock and other information, the other information representing a frequency dividing ratio between the reference clock and the audio clock of a frequency corresponding to an audio sampling frequency, said device comprising: a phase locked loop circuit including a control unit and an oscillating unit having a first voltage controlled oscillator and a second voltage controlled oscillator, the control unit being operable to detect a change in the audio sampling frequency from a signal obtained within the phase locked loop circuit, and to change an oscillation frequency range of the oscillating unit by selecting one of the first voltage controlled oscillator and the second voltage controlled oscillator when a change in the audio sampling frequency is detected, the phase locked loop circuit comprising a phase comparator coupled to a loop filter, and the control unit comprising first and second comparators to compare an output of the loop filter with first and second thresholds to generate a control signal to select one of the first voltage controlled oscillator and the second voltage controlled oscillator.