Abstract:

Today the development of electronic technology is developing rapidly,and the large scale,very large scale integrated circuit are more and more applied to general system。now new serial bus rate can be as high as dozens of Gbit·s-1,in such a rate,if the impedance of the transmission line does not accord with a standard,it would lead to serious crosstalk between transmission line,that will directly affect the quality of the PCB.In order to go further into the research on the test method of characteristic impedance,this article introduces the elementary knowledge of TDR test method and principium about characteristic impedance in PCB in detail,which presents the theoretical guidance and practical reference for the future PCB characteristic impedance test workers.

Key words: characteristic impedance;TDR;testmethod