Introduction: The PCB expert, known as ‘Water-like Man’ (with over 20 years of industry experience and a former senior technical executive at Huawei’s R&D department), previously introduced the focus on signal integrity (SI) issues in matching circuit design. This issue mainly discusses some misunderstandings in high-speed PCB design regarding high-speed signals. Water-like Man provides suggestions based on SI fundamental theory and product design engineering experience. Misunderstanding 1: Signals above GHz rates are considered…