锁相环有源滤波器设计及其对参考杂散的影响  

Design of phase-locked loop active filter and its effect on reference spur

作　　者：方明志 佘世刚[1] 周毅[1] 马沛[1] 

机构地区：[1]兰州空间技术物理研究所,甘肃兰州730000

出　　处：《现代电子技术》2014年第9期73-76,共4页Modern Electronics Technique

摘　　要：为了满足现代通信中对高频率高质量本振源的需求,采用时间常数与有源环路滤波器各元件值的关系,设计不同阶环路滤波器,并对所设计环路滤波器构成的锁相环做了ADS仿真实验;研究了不同阶有源滤波器构成的锁相环对参考杂散的抑制效果;发现50 kHz环路带宽一、二阶有源滤波器构成的锁相环对特定频偏点参考杂散抑制分别为34.09 dB与45.64 dB,100 kHz环路带宽三、四阶有源滤波器构成的锁相环对特定频偏点参考杂散抑制分别为51.77 dB与58.37 dB;结果表明高阶锁相环能在更宽环路带宽下对参考杂散有更好的抑制效果。To satisfy the need of high-frequency and high-quality local oscillators in modern communication,a different ac-tive loop filter was designed by making use of the relationship between time constants and component values of active loop filter. The ADS simulations of PLLs consisted of the designed active loop filter were performed to study the suppression effect of PLL composed of different active filters to reference spur. It is found that PLLs consisted of the first-order and the second-order active filter with a loop bandwidth of 50 KHz have reference spur suppression of 34.09 dB and 45.64 dB at a specific frequency offset point,and PLLs consisted of the third-order and the forth-order active loop filter with a loop bandwidth of 100 KHz have reference spur suppression of 51.77 dB and 58.37 dB at the same specific frequency offset point. The study shows that high order PLL can suppress reference spurs better at wider loop bandwidth.

关 键 词：有源环路滤波器 高阶锁相环 参考杂散 ADS仿真 

分 类 号：TN913.4[电子电信—通信与信息系统]