Digital Phase-Locked Loop and Noise Reduction Method with Noise Rejection

摘要

Disclosed are a digital phase locked loop and a noise canceling method having a noise canceling function. The digital phase-locked loop having a noise canceling function according to the present invention comprises a phase comparison means for comparing a phase difference between an E.F.M signal and a divided oscillation frequency signal and outputting an up signal or a down signal corresponding to the phase difference, A charge pump, a charge pump that supplies or sinks current in response to a signal and a down signal, or inverts an up and down signal in response to a control signal, and sinks or supplies a current in response to an inverted up and down signal. A low pass filter for filtering the output and outputting the signal as a direct current signal; a voltage controlled oscillation means for generating an oscillation frequency signal having an oscillation frequency in response to a direct current signal; and dividing the oscillation frequency signal at a predetermined rate, A division means for outputting to the phase comparison means and a low frequency noise component in the E.F.M signal And low frequency detection means for outputting a control signal for controlling the charge pump in response to the detected result.