In actual operation, factors such as cost, power consumption, and performance should be taken into account. Generally, complete matching is not pursued, as long as the interference such as reflection caused by mismatch is limited to an acceptable range.
Trace closed loop inspection rules: Prevent signal lines from forming self-loops between different layers. Such problems are prone to occur in multilayer board designs, and self-loops will cause radiated interference. 9) Branch length control rules for routing: try to control the length of branches, the general requirement is Tdelay<=Trise/20.