This paper discusses an all digital phase-locked loop with a zero-crossing detector and a loop filter. 本文讨论的全数字锁相环包括过零检测器和环路滤波器。
The zero-crossing PLL i.e.hardware PLL, is comprised of PFD ( Phase-Frequency Detector), loop filter, VCO ( Voltage Control Oscillator) and frequency divider. It is really simple but poor in dynamic performance, and even worse in phase lock effect with distorted input voltage. 过零锁相即硬件锁相(PLL)由鉴相器、环路滤波器、压控振荡器及分频器组成,其原理和结构较简单,但动态性能较差,且在畸变电压输入时锁相效果变差;
Ased on the zero-crossing theory, a new kind of edge detector with orientation selectivity and variable scale is presented, and its discrete B spline form under a small scale is also given. 根据过零交叉的视觉机理,提出了一种具有方向选择性和变尺度的特征检测算子,并以B样条形式给出了其小尺度下的离散化图象处理形式。
The Performance of a Digital Phase-Locked Loop with a Zero-Crossing Detector 使用过零检测器的数字锁相环的性能
As a zero-crossing detector, LoG operator is sensitive to gray scale variation, is not easy to be interfered by non-uniform light field and can detect second order zero-crossing point that can accurately reflect local gray scale variation. LoG算子作为一种零交叉检测器对局部灰度变化敏感,不易受非均匀光场的干扰,可检测出能较准确反映局部灰度变化的二阶过零点。
A Directional and Scale-Variable Zero-Crossing Edge Detector 具有方向性、变尺度的过零交叉特征检测算子
To meet the high speed requirement, a dynamic zero-crossing detector and current source to realize a precision charge transfer. It has a simple structure, high speed, small area. 针对高速的要求,采用了基于过零检测器的开关电容电路来实现采样保持功能,具有结构简单、速度快、面积小等优点。