锁相环路（PLL）

Abstract—This paper proposes an enhanced scheme for a traditional phase-locked loop (PLL) frequency synthesizer based on the integration of self-injected locking and in-loop mixing (SIL-MIX) techniques. This approach significantly reduces the overall phase noise of the conventional PLL frequency synthesizer. Additionally, the integration of a programmable phase shifter on the system provides a novel perspective for the on-board implementation of frequency synthesizers.