Signal Integrity Analysis Technology Based On Vector Network Analyzer

This paper studies signal integrity analysis technology based on vector network analyzer.It aims to use this instrument to observe the ability of maintaining signal integrity of a device under test or high-speed link.The research not only opens up new capabilities of vector network analyzers,but also brings new methods to signal analysis.The basis of this paper is the scattering parameters measured by the vector network analyzer,through which,the reflection response and transmission response of the device or the link under test can be observed.So that the impact on the signal integrity can be known.However,in the time domain,the signal integrity is generally observed by the eye diagram,which is more intuitive and simple.Therefore,the focus of this paper is to generate eye diagram by using the scattering parameters measured by the vector network analyzer.The scattering parameters are the frequency domain data,including amplitude and phase.According to the research of this dissertation,the frequency domain data needs to be transformed into the time domain data.This change can be realized by Fourier transform.First,some technical details of transforming frequency domain to time domain are introduced in detail,including discrete sampling,window function,normalization,etc.The DC value is obtained by DC extrapolation and the complete scattering parameters are obtained by the conjugate symmetry method.According to the research,the time-domain response of the scattering parameters is obtained.Second,the output response can be obtained by the convolution of the random pattern sequence and the time domain response.And then superimposed on the output response can get the corresponding eye diagram.In addition,this paper also studied the function of inserting jitter,pre-emphasis and equalization.Inserting jitter to input signal can simulate the real transmission signal while pre-emphasis and equalization can make a closed eye open.The impact of the above techniques on signal integrity can be reflected in the eye diagram results.In the end,this paper uses C++ programming language and QT software to develop a signal integrity analysis software based on vector network analyzer.According to it,people can simultaneously observe the parameters in time domain and frequency domain.People can also observe the eye diagram of the signal passing through the device or link under test.The research of this article has broken the limits of traditional instrument usage and promoted the development of cross-field signal analysis technology.It promotes the development of cross-domain signal analysis techniques.