Radar Digital Circuit Board Fault Diagnosis And The Realization

As the automatic test system is most widely used in national defense and military fields which are developing fast, weapons and equipment research and development, use and the need of ATS in the process of maintenance are the powerful motive force in promoting the development of ATS and ATS technology. Radar, as an indispensable weapon,plays a very important role in modern national defense and military fields; therefore, the maintenance and repair of radar equipment is of great significance.Modern radar equipments, at the same time, are becoming digital system. Digital circuit boards, with their specific performance, can be used for a long time, and are not easy to be renewed. When the circuit board goes wrong, it must be repaired promptly so as to make sure the radar equipment is in good condition. Therefore, it is imperative to study the fault diagnosis technology of digital circuit boards.This thesis focuses on the fault diagnosis of digital circuit boards,by fully combining the testing resources of automatic test system with the related methods for fault diagnosis of digital circuit.After analysing some classical radar circuit boards, this thesis summarizes the structural characteristics of read-only memory(ROM) of the radar digital circuit boards, raises some implementing schemes for ROM testing, and elaborates the testing process of digital circuit boards by giving the example of the representative timing circuit boards with multi-ROM. The main work and achievements are as follows:First, the allocation of testing resources of the automatic test system are grasped enough to exert excitation signals and collect the response of all signals. The fault diagnosis of the timing circuit board was finished in this paper,including the analysis of the working principle and the requirements of fault diagnosis, the compilation of diagnostic flow chart, and the design of ITA.Second, by using Multisim8 circuit simulation tools to simulate some of the circuits in the radar circuit boards, some relevant test data was obtained in this paper, which can be used later as reference to the fault diagnosis of the radar circuit boards. In the meantime, the method of using its powerful virtual instrument function to exert excitation signals in the process of Multisim8 simulation can guide us in the actual test how to exert proper excitation signals on the circuit board under test.Third,by combining the test resources of the automatic test system and the methods for fault diagnosis of the circuit board(such as function test,descending method,isolation method) with the specific configuration of the modular instrument (such as configure digital I / O to send address signals to the ROM being tested and to acquire output data in real-time), fault diagnosis of the circuit modules was made concretely and the program of the circuit module TPS was developed in this paper.Fourth, by combining the diagnostic testing strategies of the specific radar digital circuit boards on the basis of the self-developed TPS, The function of fault location was realized and the feasibility of these methods was verified in this paper.