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本文介绍了一个测试程序,该程序在具有接收机噪声和脉冲干扰(例如由雷达装置造成的干扰)的情况下测定了锁相环路解调器捕获所需信号和维持锁定的能力。对一个典型的空间测量接收机,在宽范围的锁相环路工作条件中进行了测量。测试时加以变化的锁相环路参数和干扰信号的参数包括下述项目:所需要的信噪比,信号对干扰的比率,脉冲载波频率对需要信号的偏离,脉冲宽度,干扰信号的脉冲重复率和接收机的跟踪带宽。在正常信号接受,信号哀落和具有脉冲干扰信号时捕获信号的情况下,锁相环路的性能是在所选择的各种测试条件下经过重复测量来检定的。利用电压控制振荡器的输入电压作为测量对象来记录振荡器的扫描,信号或干扰的捕获以及失锁。从测量结果中得出了能引起锁相环路假锁和失锁问题的脉冲干扰特性的范围。一般说来,干扰的影响,与模拟的雷达占空因数有很大的关系,而且也受到振幅,有用信号和无用信号之间的频率间隔,以及工作的信噪比的影响。
This article describes a test program that measures the ability of the phase-locked loop demodulator to capture the desired signal and maintain the lock with receiver noise and impulsive interference such as that caused by radar equipment. For a typical space-measuring receiver, measurements were taken over a wide range of phase-locked loop operating conditions. The parameters of the phase-locked loop (PLL) parameters and interfering signals that are varied during testing include the following: the desired signal-to-noise ratio, the signal to interference ratio, the impulse carrier frequency versus the desired signal offset, the pulse width, the impulse repetition of the interfering signal Rate and receiver tracking bandwidth. In the case of normal signal reception, signal snapping and signal acquisition with impulse interference signals, the performance of the phase-locked loop is checked by repeated measurements under the various test conditions selected. The use of voltage-controlled oscillator input voltage as a measurement object to record the oscillator scan, signal or interference capture and loss of lock. From the measurement results, we can get the scope of the impulse interference characteristic which can cause the false lock and the unlocking problem of PLL. In general, the effects of interference are strongly related to the simulated radar duty cycle and are also affected by the amplitude, the frequency separation between the wanted and wanted signals, and the signal-to-noise ratio of the work.