Patent ID: 8659323

Claim:
A frequency synthesizer comprising: a delta sigma modulator that outputs an input value to a sequentially changing digital value; an analog path unit that converts the digital value to an analog value according to a first conversion gain; an accumulator that accumulates a difference between the input value and the digital value; a digital to analog converter (DAC) that compensates an output value of the accumulator according to a second conversion gain; a correction loop that extracts analog tendency by adding an output of the analog path unit and an output of the DAC and that extracts digital tendency from an output of the accumulator and that adjusts the second conversion gain by comparing the analog tendency and the digital tendency; and a voltage control oscillator that generates an output frequency using a output of a loop filter that is extracted from a adding value of an output of the analog path unit and an output according to an adjusted second conversion gain of the DAC.