Common To The Circuit Board Automatic Test System Design And Technical Research

The main content of this paper is the general design and correlative technique of the general automatic testing system for circuit board. The fault test, fault location and fault distinguish for circuit board is called as circuit board testing. It is a very hard task to design a kind of general testing system for varieties of circuit board. For the sake of realizing the versatility of this testing system, the thesis analyzed the basic makeup unit and the variety component of circuit boards, abstracted the mutual testing requirement, built the testing frame for circuit board, and discussed the general designing of testing system. The method of fault check and diagnosis for the design of this testing system was introduced. This paper mainly discussed the method of distinguishing analog signal because of the complexity of the analog signal. Two testing and distinguishing methods for analog signal are studied and realized. One of them is called the frequency identification technique of cosine and sine wave signal based on discrete Fourier transfer (DFT), the other is called the recognizing technique of multi signals using radial-basis function (RBF) network. As to fault diagnosing, two methods are realized, one for the digital circuit diagnosing is named as fault dictionary method base on pseudo-exhaustive testing, another for the analog circuit diagnosing is named as fuzzy fault dictionary method. The idea of computer equipment is introduced to the design of this automatic testing system in which personal computer act as a main control component. In this system software replaced part work of hardware, which enhanced the flexibility and versatility. A minimum general automatic testing system for circuit board is completed. To evaluate the testing system, this system is applied to testing a kind of circuit board. The result shows that the testing system has the characters of the strong generality, high automation and easy operation.