1. Introduction
Now is the era of high-speed digital signal transmission, and the dominant transmission uses differential signal transmission lines. Suppose single-ended signals are still used to transmit at high frequencies. In that case, the signal will produce serious crosstalk, so the differential signal is used as the signal transmission method in most high-speed digital circuit systems.
However, when the differential signal is transmitted on a printed circuit board (PCB), there are still many problems caused by unsatisfactory characteristics, such as inhomogeneous dielectric, unequal time delays, or the rise and fall time of complementary signals that are inconsistent. The above problems are unavoidable and cause mode conversion—the signal changes from differential mode to common mode. In addition, the common-mode signal is also called “common mode noise” because the…
