基于SCA软件无线电的数字中频系统设计

Design of Digital IF System Based on SCA Software Defined Radio

数字中频是软件无线电平台的核心组成部分,对A/D,D/A性能有很高的要求。根据软件无线电SCA规范,在已有的基带系统基础上,通过对器件选型、参数设定、滤波器设计等关键部分的详细分析,设计了一套与之匹配的数字中频系统,主要包括AD6645完成模数转换,AD9772A完成数模转换,以及CDCM7005专用时钟芯片为各部分提供时钟。该数字中频系统以FPGA为桥梁,由DSP管理系统进行统一管理,具有完全的可编程性,允许通过加载不同的软件来实现不同的功能。

Digital IF system is the core part of software defined radio（SDR） platform, which has high requirements on A/D, D/A performance. According to the software defined radio SCA specifications, through detailed analysis of the devices selection, parameter setting, filter design and other key parts, a digital IF system based on the existing baseband system is designed, mainly included AD6645 completing analog-to-digital conversion （ADC）, AD9772A completing digital-to-analog conversion（DAC） and a special clock chip CDCM7005 providing clock for each section. The digital IF system using FPGA as a bridge, uniformly managed by DSP management system, with full programmability, allows loading different software for different to achieve different function.