Patent ID: 7409665

Claim:
A method for checking a return path of a printed board, the method comprising: detecting a signal wiring pattern with reference to wiring information of the printed board; tracing along a longitudinal direction of the signal wiring pattern while detecting whether or not a guard ground exists within a distance from the signal wiring pattern to a predetermined first discriminant value GL; identifying a non-guard ground section in which no guard ground exists within the distance from the signal wiring pattern to the first discriminant value GL; setting a second discriminant value GU which is larger than the first discriminant value GL; detecting whether or not a guard ground exists within a distance from the signal wiring pattern to the second discriminant value GU in the identified non-guard ground section; and judging an error of guard ground when it is detected that no guard ground exists within the distance from the signal wiring pattern to the second discriminant value GU in the identified non-guard ground section.