Analysis And Research Of Jitter In Time And Frequency Domain

Jitter is one of the main reasons that affect high-speed serial link data transmission,only efficient and accurate analysis of jitter,tracing its roots,and then taking measures to reduce the impact of jitter.The impact of different modules on the transmission signal in the high-speed serial link can be described by different jitter components,which then play a role in diagnosis and debugging.The jitter component and its time-domain/frequencydomain characteristics provide information for studying the type and size of the jitter component contained in the jitter process.How to extract various jitter components efficiently and accurately is an existing problem in jitter research.The research content of this paper mainly includes the following points:(1)Extraction of jitter.The software phase-locked loop with simple structure and flexible parameter design is studied,the PLL mathematical model is established,and the coefficient selection of each module of the software phase-locked loop is analyzed,The software program realizes the phase detector based on multiplication,PFD and Hogge,The software phase-locked loop algorithm of the device has verified the feasibility of the software phase-locked loop to extract jitter.(2)Time domain analysis of jitter.Study the jitter sequence histogram,bathtub curve and Q-Scale curve to predict the total jitter value under a smaller bit error rate;analyze the jitter components of the high-speed serial link to give the multi-threaded data correlation jitter extraction method;Then further improve the efficiency of jitter separation,establish a new jitter model,construct a coefficient matrix,and directly extract PJ,RJ,ISI and DCD using the least square jitter separation method,which requires less input data than traditional jitter separation methods.(3)Frequency domain analysis of jitter.According to the characteristics of different jitter components,researched and realized the extraction of periodic jitter and random jitter from the Fourier spectrum.A multi-resolution power spectrum calculation method is studied,which can ensure a reasonable frequency resolution distribution of the power spectrum curve while doing a small number of FFTs.Then,the conversion formulas between single excitation noise,multiple excitation noise and time jitter are analyzed.Study how to calculate the random jitter value in a certain frequency range of interest,and use Matlab simulation to verify the feasibility of converting the jitter from the phase noise curve.The research content of this paper is applied to the serial data analysis module of the oscilloscope software platform,which improves the accuracy and efficiency of jitter analysis,and enriches the content of oscilloscope jitter analysis.