PRINTED CIRCUIT BOARD RETURN ROUTE CHECK METHOD AND PRINTED CIRCUIT BOARD PATTERN DESIGN CAD DEVICE

摘要

A printed circuit board pattern design CAD device includes: a signal wiring pattern detection unit (22) for referencing printed circuit board wiring information so as to detect a signal wiring pattern; a guard ground detection unit (23) for tracing the signal wiring pattern along its longitudinal direction so as to detect whether guard ground is present within the distance from the signal wiring pattern to a first judgment definition value GL, identifying a guard ground absence section where no guard ground exists within the distance up to the first judgment definition value GL, and detecting whether a guard ground is present within the distance up to a second judgment definition value GU which is greater than the first judgment definition value GL from the signal wiring pattern; and a return route judgment unit (25) for judging that a guard ground error is present if no guard ground exists within the distance up to the second judgment definition value GU in the guard ground absence section. By this method, it is possible to check the return route at a high speed without any check mistake.