The Research And Simulation Of Space-Variable-Ditital-Filter

The track irregularity is the important source of the vehicle exiting, the mayjor factor of affecting the vehicle's amenity and stationeriness when its velocity is high, the first factor of restricting running-speed in aspect of the line, and the core matter of the line management. Inspection of track irregularity and further scientific evaluation make much sense of national railway construction.Nations such as America, Germany, Japan and France lead a longer way in the field of inspection of track irregularity than other ones in the world, and they all propose their own inspecting principles and analyzing methods. Basing on the digestion and absorption of advanced techniques of above countries, our country, according to native status of railway management, proposes an inspecting method of analogue-digital concatenation system. So this paper performs an exploratory research on this system, and gets quite a satisfactory result.This paper describes the character, the style and the significance of track irregularity; expounds the basic theory of space transform analysis, which includes three parts of continuous space transform analysis, discrete space transform analysis and space acquisition theorem; and what's more, researches on the relation of time and space, getting the basic relational expression of time-space. In addition, this paper points out the limitation of time transform analysis method by which we attempt to obtain the space spectrum of the actual track irregularity.After that, on the base of inertia-reference-method this paper details the process of signal's distortions: the distortion of frequency transform caused by sensors and the distortion of amplitude and phase caused by anti-confusion filter. And all result from the analogue system at forestage. At the same time, this paper designs the space-variable-digital-filter basing on the Ls acquisition, better compensating the signal's distortions occurring at forestage system. The analogue-digital concatenation system removes the effect of speed, making the acquiring data reflect truly the irregularity wavelength. Furthermore, MATLAB-Simulation proves the preliminary feasibility of the whole method. In the end, the paper shows the limitation of system which bases on the Ts acquisition.