The fault diagnosis of the printed boards of analog repeater in the program-controlled digital switching system

The analog repeated in the JD-1024 program-controlled digital switching system is characterized by the analog circuits mixed with digital circuits and machinery parts mixed with electric parts on the printed circuit boards. In view of this, in digital circuits a pseudo exhaustive method is used to create test codes. For analog circuits, the different parts are diagnosed by different methods which include dictionary diagnosis and node-multifrequency fault diagnosis. A series of tactics are used in practice which include the semi-period search method, carrying out comprehensive judgement on the multi-output function so that the test is hastened and the fault cover ratio is increased