Signal Analyzing And Modelling Of ADSL

Transmition velocity relys on the style of encode and modulation essentially during modern data transmition for the quality of using line bandwidth and the immunity of code ties on them tightly. But it is important that the velocity of data transmition reaches its limitation in fact for the interface of environment and cross-talk. So for the improvement of transmition velocity, we must analyze the characteristics of noise signal and the model of line deeply and then take some useful measures to better the immunity of modulation wave.This article takes hanging off and wide fluctuation of transmition velocity of ADSL as example, then analysis centers on the discerte multiple tone and the principle of channel load assignation. From analysis above article points out the root of ADSL being sensible of noise signal. At last, reserches effects that window function and barrier effect on frequency and adopts FFT to work out the noise power of ADSL. All these gives reliable bases for the test of ADSL.This article analyzes the qualities of AR-model, MA-model, AR-MA-model deeply during ADSL modeling. On these bases, AR-model becomes our first choice . During modeling article takes measure of Levinson-Durbin to design out desired model power. Article adopts Burg method to calculate the relation function after comparing the advantages of some parameter calculation methods. The analysis of stability and error indicate that this model meets the needs of fact.ADSL line test is a part of our design, so it must under the control of higher level controller and there are multi-task for higher level controller to attemper. In the last part of article the programming methods becomes stress of our topic. On base of analyzing interrupt response time and task-switch time and task-attemperring time This article implements a method of transplanting ucos to c51 controller.In the last part of this article, some problems need to be resolved is put forward and prospects some new techlonogies in Signal analysis for the purpose of improving the development of the study.