Title: Non-integer frequency division synthesizer and correlated method thereof
Application Number: 200610136341 Application Date: 2006.10.16
Publication Number: 1960186 Publication Date: 2007.05.09
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H03L7/18;H03B21/02;H03M3/02
Applicant(s) Name: Mediatek Inc. Address:
Inventor(s) Name: Yuan Wei
Attorney & Agent: taohai ping
Abstract:
    A frequency synthesizer includes: a phase detector, a loop filter, a controllable oscillator, a frequency divider, and a sigma-delta modulator for providing the division factor according to an integral part and a fractional part. The sigma-delta modulator includes a controller for providing a first digital value, a second digital value and a third digital value; a first adder for combining the second digital value, the third digital value, and a digital feedback value to generate a combination result; a quantizer for quantizing the combination result to generate a quantization value; a second adder for combining the first digital value and the quantization value to generate the division factor; and a multiplier for multiplying the quantization value by a constant multiplication factor; wherein the controller adjusts the third digital value in response to the reference signal for making an output frequency resolution substantially fixed.
Time: 10