LOW-POWER LOW-PHASE NOISE SIGMA-DELTA FRACTIONAL-N FREQUENCY SYNTHESIZER USING PHASE-LOCKED LOOP

摘要

The present invention relates to a Fractional-N frequency synthesizer using a phase locked loop. And a swallowtail manner of a multi-mode frequency divider, a low phase noise negative feedback method of the air conditioning LC- voltage controlled oscillator having a frequency-synthesizer according to the invention is high-order sigma-delta modulator, a pulse. By such a configuration, the present invention Sigma-Delta Fractional-N frequency synthesizer is sigma-has an excellent spurious suppression and noise shaping function according to the delta. ; fractional-N frequency synthesizer, a phase-locked loop sigma-delta pulse-Swallow, multi-mode divider, LC- cooperation voltage-controlled oscillator