脉冲信号对载波提取锁相环的干扰分析

Analysis on the Pulse Signal Jamming the Carrier Extracted Phase-locked Loop

载波提取锁相环是电子攻击的一个重要对象。环路在不同干扰样式下的失锁门限不尽相同。大部分文献中,通常以环路信噪比6dB作为环路的失锁门限,实验中发现此门限值对人为干扰并不适用。文中就白噪声、连续波信号和脉冲信号对载波提取锁相环的干扰进行了分析,给出了脉冲干扰条件下环路失锁门限的计算方法,阐述了脉冲干扰造成环路的闪锁和失锁现象。实验数据证实了脉冲干扰条件下载波提取锁相环的失锁门限更低。

The carrier extracted phase-locked loop （PLL） is an important target in the electronic attack. The PLL has different un-locked threshold value in different jamming model. In many literatures, the PLL signal-noise-ratio （SNR） 6dB is usually taken as the un-locked threshold value of the PLL. However, it is found in the experiment that the threshold value is not applicable when signal jams the PLL. This paper analyzes the influence when the white noise, continued wave signal or pulse signal jam the carrier extracted PLL. This paper presents the calculation method about un-locked threshold value in the pulse-jamming model. The twinkling-locked and un-locked phenomena of the PLL are expounded. The experimental results indicate that the un-locked threshold value in pulse-jamming model is even lower.