一种消除hangup现象的数字相位跟踪环

A NOVEL DIGITAL PHASE-TRACKING LOOP ELIMINATING HANGUP EFFECT

为实现对输入信号相位的快速捕捉,提出了一种有效消除高信噪比下hangup现象的数字相位跟踪环(DPTL)并应用有限状态Markov链理论求解其响应时间。计算和仿真结果均表明,环路克服了hangup效应,比常规采用死区(dead zone)量化器的过零采样数字锁相环(ZC-DPLL)具有更短的稳定时间。该DPTL可应用于测距等接收信号频率已知的场合。

A novel Digital Phase-Tracking Loop(DPTL) thoroughly eliminating 'hangup' effect in high SNR is proposed to fulfil fast phase acquisition. The theory of finite Markov chains is utilized to evaluate the phase acquisition time in the presence of additive band-limited white Gaussian noise. Both of the calculated and simulated results indicate that the 'hangup' effect leading to prolonged phase transients owing to the presence of the dead zone around rad is effectively removed so phase acquisition time of the described DPTL is much shorter than that of the conventional zero-crossing DPLL utilizing a dead zone quantizer. The DPTL can be used in such applications as distance measurement where the frequency of the received signal is known.