摘要:
为了获得相干啾声信号,在压控振荡器上进行线性调频,用锁相环锁定起始频率的相位。对于高增益二阶环,当环路参数和调频率满足条件01时,调频得以实现且环路无须断开。 本文将环路方程变换为近于线性的微分方程,用摄动法给出其渐近解析解,从而获得了环路对调频波形影响的定量关系。计算机模拟结果与理论分析基本吻合。
Abstract:
It is found that the linear frequency modulation is used on a voltage-controlled oseillator and a phase-locked loop to lock its starting-frequency phase for generating a coherent chirp signal. For a high-gain second-order loop, the loop parameters and the modulating frequency rate must be chosen to satisfy the condition, O 1, and then it is possible to realize the FM on the VCO, while the loop is not necessarily broken during FM pulse.In this paper, the PLL' s equation is transformed into a nearly linear differential equation and its asymptotic solution is given by perburbation metho. Thus, the quantitative relationships about the effects of the PLL on the LFM waveform are obtained. Finally, results of simulation by means of computer show good agreement with the theoretical analysis.
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