Patent ID: 7929929

Claim:
A frequency synthesizer comprising: a frequency source generating a reference signal comprising a plurality of pulses having predetermined timing based on a reference frequency; a feedback loop comprising, a phase detector circuit; a loop filter coupled to the phase detector circuit; a controlled oscillator coupled to the loop filter and generating at an output an output signal having a desired output frequency; and a loop divide circuit coupled between the controlled oscillator output and a first input of the phase detector circuit; a non-linear circuit element coupled to a second input of the phase detector circuit and generating intermodulation distortion that causes at least one spurious signal at the output; a controller providing a loop divide number for controlling the loop divide circuit, the controller further controlling the non-linear circuit element; and a dither circuit coupled between the frequency source, the non-linear circuit element and the controller and adjusting the timing of at least some of the plurality of pulses of the reference signal under the control of a parameter associated with the non-linear circuit element, which is provided by the controller, and the dither circuit further providing a resulting jittered reference signal to the non-linear circuit element for attenuating the at least one spurious signal at the output.