Using The Theory Of Signal To Analysize Marcreconomic Model

This paper analyze the multiplier-accelerator model of the macroeconomy farther, which was introduced by Keynes, applying the theory and idea of the signal and system. Many standies have indicated the macroeconomy depicted by multiplier-accelerator model is a linear system S, and the model is classic linear model. Consequently, the result of multiplier-accelerator model can be regarded as the output signal OUT which is the effect of system S on input singal IN. And so it is proper that we investigage the model by the theory and idea of the signal and system. Using the theroy of the signal and system, the conclusions of investigating multiplier-accelerator model indicate that the economic character such as Gross National Product Y(t) is linear response of the system on input singal G(t) essentially. Furthermore, the fact that the effect of the input singal and system parameters on macroeconomy is found thoroughly shows the new method overcomes a series shortcomings which are producted in the solving process of applying the method of matrix.In this paper, the error between real data and the analysized obtain by the defect of model is considered as the noise response of linear system to research the sensitivity of the classic linear model and the accuracy of the obtain. Furthermore, by studying the available range of model and the reliability of result, we obtained the available range of classic linear model. These conclusions indicate that it is impossible to forecast in long term by linear model. All of these new results and contentions not only is out of the traditional analyzing method, but also embody the great effect of the theory of the signal and system on linear dynamic model.