Prediction of Phase Noise and Spurs in a Nonlinear Fractional- ${N}$ Frequency Synthesizer
Prediction of Phase Noise and Spurs in a Nonlinear Fractional- ${N}$ Frequency Synthesizer
复制标题
非线性小数${N}$频率合成器中相位噪声和杂散的预测
DOI：
10.1109/tcsi.2019.2925181
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Michael Peter Kennedy
中科院分区：
文献类型：
--
作者：
Yann Donnelly;Michael Peter Kennedy
整数边界杂散出现在分数阶- ${N}$锁相环的环路响应通带中，因此是相位噪声的潜在重要组成部分。尽管有措施保证无杂散调制器输出，但来自分频控制器的调制噪声与不可避免的环路非线性的相互作用产生了这种杂散。本文给出了分频控制器输出和具有静态非线性的锁相环环之间相互作用产生的杂散和伴随噪声底电平的位置和幅度的分析预测。一个关键的发现是，杂散的位置和幅度可以估计仅使用的结构知识和累积调制器噪声的pdf和非线性。这些预测也为马刺出现的原因提供了新的见解。
Integer boundary spurs appear in the passband of the loop response of fractional- ${N}$ phase lock loops and are, therefore, a potentially significant component of the phase noise. In spite of measures guaranteeing spur-free modulator outputs, the interaction of the modulation noise from a divider controller with inevitable loop nonlinearities produces such spurs. This paper presents analytical predictions of the locations and amplitudes of the spurs and accompanying noise floor levels produced by interaction between a divider controller output and a PLL loop with a static nonlinearity. A key finding is that the spur locations and amplitudes can be estimated by using only the knowledge of the structure and pdf of the accumulated modulator noise and the nonlinearity. These predictions also offer new insights into why the spurs appear.