Research And Design Of Equalization Technology In High Speed Parallel Link

With the continuous development of high-speed full links,the transmission rate of signals has been increasing,and the signal integrity problems in passive links are gradually becoming prominent.How to consider the performance of the system and guide the design of the link in the early stage of designing the full link becomes an important part in current signal integrity.Studying high-speed transmission signals and interface circuits is a prerequisite for solving problems,and introducing equalization techniques based on these problems has become a new trend.The main function of the equalization technique is to compensate the high-frequency loss of the signal through the channel making the highfrequency components and low-frequency components of the signal relatively balanced This mitigates the tailing of the signal passing through the channel and reduces the symbol existing in the high-speed signal.Therefore,by selecting a reasonable equalization technique,the problem of low signal data transmission rate and high system error rate can be effectively solved.This paper analyzes the signal integrity problems in high-speed parallel links and introduces an equalization method based on these problems.The main methods are as follows: Forward Feedback Equalization(FFE),Continuous Time Linear Equalization(CTLE)and Decision Feedback Equalization(DFE).Then,according to these equalization methods,the corresponding algorithms were written,and the correctness of these algorithms was verified by setting up a high-speed link.In order to add the equalization algorithm to the model,the mainstream IBIS-AMI model was studied.The high-speed full link is built by EDA tool,and the IBIS-AMI model is added to the transmitter and receiver to achieve equalization.In order to solve the incompatible model in EDA tool and the loading problems of the single-ended signal,An equalization method which adds the IBIS_AMI model in MATLAB is proposed.The method loads the encapsulation equalization algorithm in the IBIS-AMI model.parse the parameters and pass the parameters to the derived function in the equalization algorithm to achieve AMI equalization.Finally,the correctness of the method is verified by the actual link.In this paper,the simulation software based on MATLAB Graphical User Interface(MATLAB-GUI)is developed.Various equalization algorithms and algorithms for loading IBIS-AMI model are added to the simulation software.The interface of the equalization software is introduced in detail.A simulation platform of DDR4 read mode is built toanalyze the data of the eye diagram before and after the equalization and verify the feasibility of the algorithm and the effectiveness of the balance.It has great guiding significance for the research of next-generation high-speed parallel link DDR5 equalization technology.