文档介绍：Embedded LO Synthesis Method in Harmonic Rejection Mixers Travis Forbes and Ranjit Gharpurey Department of Electrical puter Engineering, University of Texas at Austin, Austin, TX 78712 Abstract —A method for effective synthesis of multiple down- conversion local oscillator (LO) frequencies within a harmonic rejection mixer (HRM) is presented that employs principles sim- ilar to direct digital frequency synthesis. The proposed method reduces the tuning range required of the downconversion oscilla- tor in broadband applications. A passive HRM that implements the proposed LO synthesis method and is robust to both gain and phase mismatch is designed in 130 nm CMOS and covers the 48-860 MHz band with a master clock frequency of - GHz. Based on Monte Carlo simulations, while considering device mismatches over a 3σ spread, harmonic rejection better than 63 dB is observed for all selectable LO frequencies. I. I NTRODUCTION Spurious mixing within downconversion mixers presents a major challenge in the implementation of wideband receivers for applications such as software-de?ned radio (SDR) and digital TV (DTV). A primary cause of spurious mixing is the presence of undesirable harmonics in the spectrum of the ap- plied local oscillator (LO) which can lead to downconversion of interferers in the vicinity of these harmonics to baseband, along with the desired signal, thereby degra