Impact of Cross Modulation in Coaxial Connectors on Signal Distortion

Coaxial connectors generally exhibit nonlinear characteristics, even when they are pristine, which can cause cross modulation. In addition, there are phase noise and Additive White Gaussian Noise (AWGN) in broadband communication systems. All of these factors cause different levels of signal distortion and negatively impact the reliability of communication systems. In this current work, a polynomial behavior model was developed to describe the nonlinear characteristics of coaxial connectors. Based on the two-tone continuous wave (CW) testing procedure, a series of experiments were conducted to obtain the model coefficients. The Error Vector Magnitude (EVM) was selected as the index to quantify the level of signal distortion. The impacts of cross modulation, phase noise, and AWGN on EVM were theoretically calculated. Simulations were conducted to compare the impacts of different factors. The results show that cross modulation is a significant factor causing signal distortion, especially when the input power is high. This work serves to provide a theoretical basis for evaluating the impacts of cross modulation, phase noise, and AWGN on signal distortion.