It is difficult to synthesize the antenna directly in practical lessons in general theory of antennas with students. The approximate method is proposed for solving the synthesis problem based on the minimization of the functional representing the distance in the functional space with a quadratic metric between the normalized desired antenna pattern (AP) and some normalized AP with unknown amplitude and phase distribution (APD) of the field in the aperture. In this case the AP does not necessarily have to relate to the class of realizable ones, and APD of the field, while functional is minimized, can be selected from the set of the functions suitable for implementation.Validity of the method is tested on the example of synthesis of a linear antenna with the APs for which the APD is accurately known. The recommendations for conducting practical lessons are given.
The identification of the socio-economic system, which includes the scientific and scientific-technical activities of Ukraine, using the three input and output signals, is carried out in the article. The synthesis of the model is based on the minimization of the functional, which is the distance in the functional space with the quadratic metric between the real output signal and the theoretical signal containing the unknown parameters of the system model. These parameters include the system time constant and the coefficients that describe the power transformation function of the nonlinear block. A comparison of real output signals and signals calculated using the linear model of the system with memory and the Hammerstein model for a nonlinear inertial model is carried out. It is shown that the errors of the output signals representation for the quadratic model are less than for the linear one and are different for various output signals. If these errors exceed the allowable ones, it is recommended to change the parameters of the model or the number of members of the power function of the nonlinear block transformation.
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