The Design Of Portable General Box For Verifying Combination Instrument

This paper designs one kind of the portable combination verifying box which uses in the automobile measuring to verify. This paper first introduced the design request and the design background of this verifying box. Then according to the topic request designed the basic structure, and has been clear about the direction and the difficulty which this article had emphatically to study.This article mainly designed is the verifying box's two signals occurrence parts: controllable alternative current signal and controllable resistance signal, And separately introduced two kind of signals produce principle of work, basic structure and concrete realization means.The controllable alternative current signal production used the Digital Direct Frequency Synthesis (DDS) technology. The paper has used the FPGA component in the concrete realization, through the VHDL language programming, has composed the DDS essence in the FPGA chip interior, and the use Single-chip Microcomputer achievement outputs control component.The controllable resistance signal production used the MOS tube to compose had the power source controllable resistance electric circuit. This paper has designed a Search algorithm based on fuzzy algorithm as the control algorithm, basically has satisfied the design request.The paper finally has carried on the analysis to the test result, had pointed out in the design insufficiency, and gave the improvement comment.