In high-speed PCB design, crosstalk and reflection are two critical signal integrity issues that can degrade performance and cause system failure. Reflection is an energy “echo” caused by impedance mismatches along a signal’s path, resulting in ringing and distortion of the waveform. Crosstalk, on the other hand, is the unwanted electromagnetic interference between adjacent traces, where a switching signal (the aggressor) induces noise onto a nearby quiet signal (the victim). Understanding the distinct causes and effects of both is fundamental to designing robust and reliable high-speed digital circuits.