APPLICATION OF THE DECONVOLUTION METHODS FOR PROCESSING OF MEASUREMENT SIGNALS IN THE FAST PROCESSES

In practice of experiment, one had to be faced with the distortions caused by measuring equipment, especially on a limit of its resolution. Sometimes not the equipment but the investigated process itself gives the grounds for distortion of the registered data, for example, at photography of quickly moving objects. Other examples of distortion of data are measurements of temperature and forces in wind tunnels. Problems of elimination of instrument function (or response function) of the device are most often reduced to the solution of the integral equations, usually, with convolution kernels. The solution of these equations is called problem of deconvolution. In present paper, methods and algorithms of the solution of some tasks, which appear at processing the signals obtained in aerodynamic experimental researches, are presented. The regularization algorithm of the solution of deconvolution problem, adapted to the level of experimental noise, is described. Results of numerical simulation of a task of temperature correction of thermocouples (temperature gages) lag at restrictions of temporary resolution of the thermocouples and short-term process are given. The numerical solution of a non-stationary problem of heat conductivity in two-dimensional statement for determination of average temperature of the thermocouples at three values of their diameter (d=50, 100, 200 microns) was performed. Within numerical modeling, the twodimensional equations of heat conductivity by the relaxation method were solved. Experimental definition of instrument function of the thermocouples was carried in experiment with constant step thermal loading. The same type of thermal loading was used at numerical simulation. Direct comparison of the calculated and experimental data for the thermocouple with diameter of 50 microns shows that by means of calculation it is possible to receive the temperature step function close to the experimental one. Therefore, it is possible to estimate theoretical impulse response function of the thermocouple by differentiation of the calculated response function of the thermocouple to the step loading. The calculation results agree well with the temperature measurements by the thermocouple of the same size obtained by its immersion in molten aluminum. Instrument function, defined from the real experiment with immersion of thermocouples in aluminum melt, appeared to be close to the function obtained theoretically.

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