软件无线电卫星便携地面站中的直接数字频率合成器  

DDFS in a SDR Portable Satellite-Earth Station

作　　者：漆庄平[1] 李国通[1] 杨根庆[1] 

机构地区：[1]中国科学院上海微系统与信息技术研究所,上海200050

出　　处：《应用科学学报》2004年第4期463-466,共4页Journal of Applied Sciences

摘　　要：理想的软件无线电需要高效且高速的数字下变频器.通常数字下变频采用查找表方法实现,即输入信号的采样乘上一个预先存储在ROM中的正弦余弦函数值.为了得到高精度,这种方法需要很大的查找表,这就意味着占用芯片面积大、功耗大、工作速度低和增加成本.文中描述了一个基于CORDIC算法的直接数字频率合成器.它能大幅度地减少查找表的大小,从而达到高精度的要求.An ideal software radio needs efficient high speed digital down converters. The common approach for digital down conversion (DDC) is the so-called ROM table approach where the samples of the input signal are multiplied with amplitude values of the sine-and cosine-function stored in ROM. To achieve high resolution, this technique requires a large look-up table which means large chip area, high power consumption, lower speed, and increased costs.In this paper, a CORDIC-based direct digital frequency synthesizer is described. It is able to reduce the size of the look-up table considerably.

关 键 词：查找表 直接数字频率合成器 软件无线电 数字下变频器 CORDIC算法 地面站 功耗 ROM 输入信号 芯片 

分 类 号：N945.25[自然科学总论—系统科学] TN741[电子电信—电路与系统]