Patent ID: 8570107
Filing Date: 2013-10-29
Classification: H03L

Abstract:
1. A clock generating apparatus, comprising: a time-to-digital converter (TDC), arranged to convert a timing difference between a reference clock and a variable clock to generate a digital value; a calibrating device, arranged to generate a control signal according to the digital value and the reference clock; a controllable oscillator, arranged to generate an oscillating signal according to the control signal and the digital value; a feedback device, arranged to generate the variable clock to the TDC according to the oscillating signal; a digital loop filter, coupled between the time-to-digital converter and the controllable oscillator; and a sigma-delta modulator, coupled to the feedback device; wherein the calibrating device calibrates the controllable oscillator to make the oscillating signal have a target oscillating frequency, and the digital loop filter and the sigma-delta modulator are disabled while the calibrating device is calibrating the controllable oscillator.