高频信号动态测试中的信号完整性分析

结合高频信号测试仪使用环境的特点及要求,分析了影响高速数据采集电路信号完整性的主要因素,针对高频信号的反射和串扰,分别从多层PCB板的层叠设计,差分信号传输线蛇形布线,添加阻抗匹配网络几方面进行了信号完整性设计。建立差分信号传输线拓扑网络的模型并通过仿真确定了阻抗匹配网络的结构和参数,减小了由于传输线阻抗失配引起的信号反射与串扰;对电源完整性进行分析,通过内电层分割和滤波电容网络减小了电路中的地弹现象,从而降低了测试仪的系统噪声。最后通过模拟环境下的实验验证了高速数据采集电路的信号完整性分析,实验结果表明通过信号完整性设计提高了测试仪的抗干扰能力,所采集的数据可靠有效。

Signal integrity analysis in high frequency signal dynamic test

This paper analyzes the main factors affecting the signal integrity of high speed data acquisition circuit based on the characteristics and requirements of high frequency signal test instrument use environment.Aiming at the reflection and crosstalk of high frequency signal, the signal integrity design is carried out from the multi layer PCB board laminated design, differential signal transmission line serpentine routing and adding impedance matching network, respectively. The network topology model of differential signal transmission line is established, andthe structure and parameters of the impedance matching network are determined through simulation, which reduces the signal reflection and crosstalk caused by transmission line impedance mismatch. The power integrity is analyzed, the circuit ground bounce is reduced with the inner electric layer segmentation and filter capacitor network, and thereby, the system noise of the test instrument is reduced. Finally, test experimentunder simulation environment was conducted, which verifies the signal integrity analysis of high speed data acquisition circuit; the experiment result shows that with signal integrity design, the anti jamming capability of the testinstrument is improved, and the collected data are reliable and effective.