对数字有线电视调谐器中带有源滤波器结构的锁相环进行分析,深入研究了锁定时间与环路参数的关系,在推导环路相位误差的基础上,提出了一种计算环路锁定时间的方法,并给出具体的计算公式。计算结果与仿真/测试结果比较吻合,说明得到的公式能准确计算出锁定时间,而且可以直观地反映锁定时间与环路参数之间的关系。 Based on the analysis of the phase locked loop (PLL) with the active filter in the digital CATV tuner, the relationship between the lock time and the loop parameters is deeply studied. Based on the derivation of the phase error of the loop, a computational loop lock Time method, and gives the specific formula. The calculated results are in good agreement with the simulation / test results, indicating that the obtained formula can accurately calculate the lock time, and can directly reflect the relationship between the lock time and the loop parameters.