基于软件无线电的通用数字调制器的实现

软件无线电的基本思想是构造一个通用的硬件平台，将通信的各种功能尽可能用软件实现．数字上变频是软件无线电的关键技术之一，主要功能是对输入数据进行各种调制和频率变换．AD9857是通用数字正交上变频器，具有可编程性、体积小，速度快，性能高等特点．详细介绍了该器件的原理、结构与使用方法，分析了软件无线电调制算法的特点，给出了一个利用FPGA与AD9857相结合而实现通用的数字调制系统平台的实例．

General Digital Modulator Based on Software Defined Radio

The basic idea of Software Defined Radio is to structure a general hardware platform to make the most of the software to complete variety of communication functions. As one of the key technology of Software Defined Radio, Digital Upconverter modulated the input data in kinds of modes and converted it to intermediate frequency, It is difficult to implement it on Digital Signal Processor, so we should use special IC to achieve DUC. AD9857 is a Quadrature Digital Upconverter chip manufactured by ADI corporation with features such as programmable, small package, high speed and high performance. First, the authors introduce the principle, architecture and application of AD9857, and then analyse the characteristic of Software Defined Radio modulation, at last they give an instance in which they design a plat of general digital modulation system integrated FPGA and AD9857.