High-Order Modulation Signal Generator and Its DSP Implementation

Abstract

In recent years, the low-order modulation signal cannot meet current demands due to the band tension and high demand of data transfer rate. In this paper, a higher-order modulation signal generator based on software-defined radio idea was designed. The design implements an efficient plan based on DDS technology by combining the TMS320C5509 chip with CPLD, which can send and receive signals and do floating-point data operation by the method of a 16-bit fixed-point DSP calibration. The validity of the proposed method has been verified by CCS simulation of the 64 QAM, 128 QAM and 256 QAM signal constellation graph mapping.