Chapter 3 Time Domain Reflectometry
Note: This chapter is a reprint of the article “The darker side: Time domain reflectometry,” Circuit Cellar, no. 225, April 2009.
In the previous chapters I talked a lot about impedance matching. In this chapter I will present the same subject from another angle: time domain. You may have read sentences such as “When matching is not perfect, a part of the signal is reflected back to the source.” This may seem strange for engineers who are not used to high-frequency effects. Imagine the worst case of an impedance mismatch: a wire grounded at one of its ends. Do you think there could be any signal, reflected or not, in such a wire? Of course, and I will show it to you!
In the previous chapters I talked a lot ...