微系统设计、测试与控制课程大作业之基于FPGA的DDC（数字下变频）的设计与仿真1摘要..............................................................................................................................................1ABSTRACT......................................................................................................................................2第一章绪论....................................................................................................................................31.1数字下变频（DDC）研究背景........................................................................................31.2DDC概述...........................................................................................................................41.3本文研究内容和结构安排.................................................................................................5第二章数字下变频（DDC）基础理论........................................................................................62.1数字下变频器.....................................................................................................................62.1.1数字变频的基本原理与结构..................................................................................62.1.2影响数字变频器性能的主要因素..........................................................................62.2数字信号采样理论.............................................................................................................72.2.1低通信号采样理论..................................................................................................72.2.2带通信号采样理论..................................................................................................72.3数字正交检波.....................................................................................................................82.3.1低通滤波法..............................................................................................................92.3.2多相滤波结构变换法............................................................................................102.4多抽样率数字信号处理理论...........................................................................................112.4.1整数倍抽取和内插................................................................................................112.4.2多抽样率系统的恒等变换....................................................................................142.4.3多相滤波结构........................................................................................................142.5相关算法介绍...................................................................................................................162.5.1CORDIC算法........................................................................................................162.5.2FIR滤波器.............................................................................................................182.6本章小结...........................................................................................................................19第三章数字下变频（DDC）各模块设计..................................................................................203.1数字下变频的基本实现方案...........................................................................................203.2基...
