QAM signal normalization by results of it demodulation with Kalman's error minimization

Abstract

Introduction. The processes of signal processing in the quadrature demodulator, and the problem of input signal AGC and carrier sync PLL are considered for a relatively high speed modulation conditions. Main part. The basic concepts of the simultaneously implementation of input signal AGC and carrier sync PLL in the QAM demodulator are formulated. Mathematical model of the process of normalization and synchronization pre-demodulated signal elements are designed. Optimal solution of the surveillance equation with minimizing errors by Kalman is found. Results of the implementation process of normalization and synchronization pre-demodulated signal elements in QAM demodulator signals on the example of recommendation ITU-T V.29 is presented. Problem of further research to determine the minimum sufficient number of pre-demodulated signal elements for the implementation of the developed technique is announced. Conclusions. It is shown that the described mathematic model of process of input signal AGC and reference basis PLL and its solution are providing reliable demodulation of QAM signals with high modulation speed and minimizing errors by Kalman.