公开(公告)号：US06807225B1

公开(公告)日：2004-10-19

申请号：US09584598

申请日：2000-05-31

Applicant: Davide Tonietto ,  Andre M. Bischof

Inventor： Davide Tonietto ,  Andre M. Bischof

IPC: H04B138

CPC classification number: H03L7/087 ,  H03L7/10 ,  H03L2207/06 ,  H04L7/0004 ,  H04L7/033

Abstract: A circuit and method is disclosed for self trimming in frequency acquisition and clock recovery. The circuit can be simplified as having a VCO in communication with three loops including a trimming loop, a frequency loop and a phase loop. The trimming loop includes a ramp generator for supplying a steady increase of bias current to the VCO causing the frequency of the VCO to increase. At each step, the averaged output of the frequency detector is measured by a comparator. A decision circuit included in the trimming loop registers the output of the comparator in digital format. The trimming loop continues until the decision circuit detects a long string of positives followed by a long string of negatives and at this point, the trimming loop is shut off and the frequency loop is in operation. The frequency loop drives the VCO frequency to within a small difference of the incoming data frequency. The phase loop cleans up the data and locks the phase.

Abstract translation: 公开了用于频率采集和时钟恢复中的自整定的电路和方法。 该电路可以简化为具有与三个环路通信的VCO，包括修整环路，频率环路和相位环路。 修整回路包括斜坡发生器，用于向VCO提供稳定增加的偏置电流，从而使VCO的频率增加。 在每个步骤中，频率检测器的平均输出由比较器测量。 包括在微调循环中的判定电路以数字格式注册比较器的输出。 修整循环继续，直到判定电路检测到长串正序，然后是长串负片，此时，修整环路被关闭，并且频率环路正在运行。 频率环路将VCO频率驱动到输入数据频率的小差异之内。 相位循环清理数据并锁定相位。