This diploma thesis deals with the development of the test PCB design for testing various termination methods on a long transmission line at different high frequencies.
The introduction contains a description of signal integrity, relationship between signal integrity and transmission line design on PCB, relationship between devices electromagnetic compatibility (EMC) and PCB design, and line effects. Further on, the theory of transmission lines is presented: lossless transmission line and loss transmission line, characteristic impedance, basic calculations for different types of transmission lines on PCB and calculations of time propagation delay on lines. Moreover, reflections and a method for analyzing signal traveling on the line, types of terminations and practical calculations are described in further detail.
The thesis outlines the guidelines applied in test PCB designing and defines the structure and functioning of the PCB.
The analysis of a transmission line is carried out in two steps: a computer simulation of all the terminations using Spice Lt program and real measurements. We compared the shape of each signal and voltage levels. The comparison between simulations and real measurements showed, in the end, which termination was best in our PCB design and why. In determining the best results, we aimed to get as close as possible to the best match between simulations and real measurements, paying attention to the fact that the termination either weakened or completely removed reflections.
|
