Characteristics of noise on printed circuit board traces induced by noise transmitted on external cables

This study is for improving the noise immunity of electronic circuits on printed circuit boards (PCBs). The noise on the PCB traces is induced by external cables which are different from the PCB traces in length. This paper experimentally and analytically clarifies that large amounts of noise can be transferred from a noisy wire to a victim wire, even when the wires are of different length and loose coupling at a short-section. The reason why large amounts of noise are transferred is revealed that the base resonant frequency f₀ of the shorter wire´s own can be the same as the multiple resonant frequency N·f ₀ (N=2,3,...) of the other wire´s own. Further, according to the location and kinds of load such as ICs connected with the PCB trace, which is considered as a victim wire, the resonant frequency dominating the noise frequency is changed