PHASE-LOCKED LOOP DEVICE OF DIGITAL AUDIO SIGNAL

PURPOSE: To make it possible to maintain predetermined frequency by detecting rising and falling edges of a period signal of input data signals transmitted from a video system, and generating a clock signal. CONSTITUTION: The signal (fsync ) output from a second clock generator 22 is input to the one side of a first phase comparator 31, the signal of phase difference output from the comparator 31 is low pass filter-processed by a first loop filter 32 to a predetermined voltage component, and then input to a first voltagecontrolled oscillator 33. The oscillator 33 outputs an oscillating frequency varying in response to the input voltage so that, at this time, the central frequency of the oscillator 33 becomes 2l.333kHz, and when the first phase period group 30 is periodically cycled, the central frequency is maintained constantly.