Digital PLL with Observer-Controller Loop Filter

这项研究的目标是开发一种数字锁相环(DPLL)，在实现低相位噪声的同时，对干扰和传输延迟的影响具有基本的鲁棒性。方法是采用复杂的数字控制方案，以便可以在数字反馈环路中显式建模和考虑电路噪声、外部干扰和环路延迟的影响。这种方法与现有的环路滤波器不同，现有环路滤波器的带宽通常是唯一可以修改的设计参数，以减少干扰或其他非理想因素的影响。智能优点：在本项目所采用的方法中，DPLL的模拟组件被建模为状态空间形式的噪声对象。从这个角度看，控制噪声对象产生期望频率可以归结为一个线性调节器问题，这是最优线性控制理论的经典问题。本项目中开发的观测器-控制器环路滤波器广泛适用于使用锁相环的现有系统。此外，建议的数字锁相环对干扰的固有稳健性使其能够在许多新兴系统中使用，例如直接转换和反相发射机架构。广泛的影响：该研究与教育计划相结合，以帮助培养研究生和本科生。研究的多学科性质将拓宽学生的技术理解，这将是下一代工程师不可或缺的。该教育计划还包括改善本科生和代表性不足群体成员的参与程度的计划。

The objective of this research is to develop a digital phase-locked loop (DPLL) that achieves low phase noise while being fundamentally robust to interferers and the effects of transport delays. The approach is to employ sophisticated digital control schemes so that the effects of circuit noise, external interferers, and loop latency can be explicitly modeled and accounted for in the digital feedback loop. This approach contrasts with existing loop filters, whose bandwidth is generally the only design parameter that can be modified to mitigate the effects of interferers or other undesirable non-idealities.Intellectual Merit: In the approach pursued in this project, the analog components of the DPLL are modeled as a noisy plant in state-space form. When viewed from this perspective, controlling the noisy plant to generate the desired frequency can be posed as a linear regulator problem, which is a classical problem of optimal linear control theory. The observer-controller loop filter developed in this project is broadly applicable to a wide range of existing systems that employ PLLs. Furthermore, the inherent robustness to interference of the proposed DPLL enables its use in many emerging systems such as in direct-conversion and out-phasing transmitter architectures.Broader Impacts: The research is integrated with an education program to help train both graduate and undergraduate students. The multi-disciplinary nature of the research will broaden the students' technical understanding, which will be indispensable for the next generation of engineers. The educational program also includes plans to improve the participation of undergraduate students and members of underrepresented groups.