Speeding-up Phase-Locked Loops based on Adaptive Loop Bandwidth

Abstract

This paper describes three techniques for controlling the loop filter of the PLL for high operating speed. The proposed fastlocking PLL reduces the pull-in time and enhances the switching speed, while maintaining better noise bandwidth. Extended loop bandwidth enhancement is achieved by the adaptive control on the loop filter resistances. This work differs from previously published results in that it presents a comprehensive study for modeling, circuit simulation and practical circuit implementation of a 2nd order PLL with loop filter control for speeding-up the PLL. The overall improvement in performance of the proposed PLL is evaluated and compared with the conventional PLL. An industrial CMOS IC is used to implement the PLL.

Signal Frequency Estimation Based on Kalman Filtering Method

“…Phaselocked loop is the most commonly used in satellite signal processing frequency estimation method [1][2][3][4], but under high dynamic conditions it requires using higher-order loop, which cause stability problems. Kalman filter is an optimal estimation method, with excellent performance and noise filtering characteristics predict [5,6].…”