The Research On Test Method Of Characteristic Impedance In PCB

Today the development of electronic technology is developing rapidly, and thelarge scale, very large scale integrated circuit are more and more applied to generalsystem. Now the integration of integrated circuit is becoming higher and higher, thereare a large number of devices and chips on the circuit board. Chips are connected withhigh-speed serial bus connection, and now new serial bus rate can be as high as dozensof Gbps. In such a rate, if the impedance of the transmission line does not accord witha standard, it would lead to serious crosstalk between transmission lines that willdirectly affect the quality of the PCB. PCB manufacturers and designers need highprecision impedance test equipment, so that in the production and design process theycan control the impedance of the signal transmission line, design and produce PCBwith high quality.This thesis does research on the characteristic impedance test method in PCB,from the transmission line theory, the basic concepts and characteristics ofcharacteristic impedance to the common characteristic impedance test standard, the testmethod and the test equipment. At the same time the TDR (Time DomainReflectometer) basic principle of measuring the characteristic impedance, the TDRresolution, the TDR equipment precision and the calibration method are researcheddeeply. And with the reference to IPC-TM-650standard, the basic operation procedureand the simulation method of testing PCB characteristic impedance with TDRinstrument is also given, which presents the theoretical guidance and practicalreference for the future PCB characteristic impedance test workers.