Communication System Of Full Digital Carrier Recovery Technology Research And Implementation

In the context of today’s digital communication is an urgent need for large amount of information transmission system. Modern digital communication systems have been great demand for the modulation and demodulation of reliable high-speed data transmission. Because quadrate amplitude modulation (QAM) techniques are high spectrum efficiency, and its anti-noise performance is strong, it can be used in the field of digital microwave communications.Signal transmission in QAM communication systems, frequency offset and phase offset resulted by the factors of channel and receiver which will have an enormous impact in demodulation. In order to correct the frequency offset and phase offset, the signal to achieve accurate demodulation, carrier recovery module has become an indispensable part of the receiver.This paper studies the optimization and simulation of the and FPGA Implementation of high order QAM signal. These carrier recovery algorithms are digital methods. In the case of ensure the algorithm functions made some improvement. In the FPGA implementation, in the thinking of the resources, make the optimization of algorithm.The works of this paper are:First:Described in detail the principle of QAM modulation. Analysis the classic commonly used carrier recovery algorithm which is maximum likelihood algorithm reduced constellation (RC) algorithm and decision directed (DD). Describes the conditions of application of several algorithms and their respective shortcomings.Second:Described the two all-digital receiver system design, especially the carrier recovery module in detail. Study the polarity decision algorithm for high order QAM signal carrier recovery, and its improvement. Verify the correctness of the algorithm by simulation and analysis.Third:For achievement for FPGA of Polarity decision algorithm to introduce the hardware platforms and the division of modules. For each module of carrier recovery, made description for achievement and simulation. Finally verify the correctness of the implementations.