近年來由於高頻與低電壓操作之時脈源需求與日俱增，有鑒於此，本論文將提出一採用新穎式倍頻與小數相位迴旋技術之頻率合成器。其中倍頻電路主要是將再生四相位壓控振盪器尾部訊號的兩倍頻率，且讓頻率合成器能達到更大輸出振幅與更高操作頻率之需求。此外，亦針對第一級除頻器與預除器提出新式折疊與相位迴旋技術，進而讓系統能於超低電壓操作條件下進行小數除頻操作。經驗證結果顯示，當系統全速度操作時，具有倍頻機制之四相位壓控振盪器與後級除法電路皆可操作於0.5伏特電源電壓，此時頻率合成器總銷耗功率約為12mW。而當載波頻率設定於9.088 GHz時，時脈相位雜訊於1MHz偏移處約-105 dBc/Hz。

To lower the supply voltage for high-frequency operation, a fully integrated frequency synthesizer, together with regenerative frequency-doubling and fractional phase-rotating techniques, is presented. The frequency-doubling circuit regenerates the tail signals at twice the frequency of the quadrature voltage-controlled oscillator (QVCO) to achieve larger output swing and higher operating frequency for the synthesizer. Additionally, a hybrid circuit utilizing a new folded regime for the first-stage divider and the phase-rotating circuit is developed in the prescaler. Under full -speed operation, the QVCO with the frequency doubler and the divider can work from a 0.5-V supply, whereas the synthesizer dissipates 12 mW. At 9.088 GHz carrier frequency, the measured phase noise is -105 dBc/Hz from 1 MHz offset.