正交调制器包络时延测量新方法

New Method of the Quadrature Modulator’s Envelope Delay

在高精度卫星测控、导航定位领域,系统链路的时延测试准确度是影响测距精度的主要因素之一。正交调制器作为系统链路的重要组成部分,由于其输入输出信号的特性差异,难以使用相位延迟进行时延测试。通过对正交调制器基带输入伪码跳变沿的不确定性、射频相位翻转点的不确定性和测量重复性等问题的分析,提出了基于包络时延的正交调制器测量新方法。使用Simulink通信工具箱验证了新方法测量原理的正确性,给出了基于最大似然原理的正交调制器时延估计模型推导过程。设计了由基带信号发生器、正交调制器和数字示波器组成的时延测量试验装置。实测试验结果波形均与理论波形相吻合,表明了该方法的可行性。与传统测量方法相比,新方法消除了人工判读输入输出信号跳变沿引入的误差分量,时延测量分辨率可达数字示波器的最小采样间隔。

In the field of high-precision satellite measurement and control,navigation and positioning,the measurement accuracy of the time delay of system is one of the main factors of the accuracy of distance measurement.Quadrature modulator,as an important component of system link,because of the difference in characteristics of its input and output signals,it is difficult to use the phase delay to test time delay.Through analyzing the uncertainty of the transition edge of input pseudo-code of the baseband of quadrature modulator,the uncertainty of RF phase flip point,and the measurement repeatability,a new measurement method of quadrature modulator based on envelope delay is proposed.Simulink communication toolbox is used to verify the correctness of the measurement principle of this new method.The derivation process of time delay estimation model for quadrature modulator based on maximum likelihood principle is given.A time delay test device consisting of a baseband signal generator,a quadrature modulator and a digital oscilloscope is designed.The waveforms of the experimental results are consistent with the theoretical waveforms;which indicates the feasibility of the method.Compared with traditional measurement methods,the new method eliminates the error component introduced by the artificial interpretation of the transition edge of the input and output signals and the resolution of time delay measurement is up to the minimum sampling interval of a digital oscilloscope.