| 摘要 |
PURPOSE:To achieve a higher speed of diagnosis of a large logical circuit, by finding a sequence circuit searching a loop matrix of directed graph to divide it into blocks of a combination circuit. CONSTITUTION:A flip flop is made up of gates G14 and G15 and a trouble diag nosing of a logical circuit containing a loop connection for making a feed back from the gate G14 to a gate G8 is conducted with an electron beam tester, a laser probe or the like. With gates G1-G15 considered as contacts, the logical circuit is divided into blocks of a combination circuit detecting the existance of a loop of a partial graph generated with inter-gate nets 1-29 made corre sponding to directed branches in such a manner that each line of the loop ma trix will surely contains 1 and -1 1 elements. The partial graph is formed by adding directed arms and contacts along the direction of the circuit from input terminals a-o. Furthermore, when additional arms are provided to form a large graph, the arm finally added shall be arranged to be a cut branch be tween the blocks if the element of each line in the matrixes is neither 1 nor -1 with the addition thereof. |
