说明：  随着数模转换器硬件的快速发展和DSP处理能力及处理速度的逐步提高，软件无线电技术在商用和军用无线电通信领域也越来越显示出其强大的吸引力。本文研究的高速中频采样和数字下变频技术是目前蓬勃发展的软件无线电领域的两项关键技术。
(As advances in technology provide increasingly faster and less expensive digital hardware, more of the traditionally analog functions of a radio receiver will be replaced with software or digital hardware. The software radio has show its fascinating functions in both commercial and military wireless communication. The high speed and high resolution analog-to-digital converter and digital down-converter which are researched in this thesis are two of the key technologies in the field of software radio that is vigorously developing recently.)