1、毕业论文 摘 要 直接数字频率合成(Direct Digital Synthesis， DDS)是 20 世纪 60 年代末出现的第 三代频率合成技术，该技术从相位概念出发，以时域采样定理为基础，在时域中进 行频率合成，它以可编程逻辑器件(CPLD)作为控制及数据处理的核心，可将波形数 据用 D/A 转换器快速恢复。基于 CPLD 和 DDS 技术的函数发生器可以实现信号波 形的多样化，同时大大提高输出信号的带宽。 整个设计采用 MAX+ plus II 开发平台，VHDL 编程实现，基于可编程逻辑器件 CPLD 设计多波形信号发生器。用 VHDL 编程实现，其设计过程简单，极易修改， 可移植
2、性强。 系统以 CPLD 为核心， 采用直接数字合成技术， 辅以必要的模拟电路， 构成一个波形稳定，精度较高的函数信号发生器。系统的特色在于除晶体振荡器和 A/D 转换外，全部集成在一片 CPLD 芯片上，使系统大大简化。它可输出频率、幅 度可调的正弦波、三角波、方波。另外由于 CPLD 具有可编程重置特性，因而可以 方便地更换波形数据，且简单易行，带来极大方便。 关键词：关键词：信号发生器设计；三相；VHDL；CPLD；MAX+ plus II 毕业论文 ABSTRACT Direct digital frequency synthesize(DDFS) is a recently and
3、rapidly developed technology which features high frequency resolutionThis paper briefly introduces the basic principle of DDS. The basic principle and performance of CPLD chipThen it mainly describes how to use CPLD chip to design a function generator of high accuracyThe principle of three-phase mul
4、ti-signal generator based on CPLD and DDS technology is introducedBased on these，the modules of CPLD design are given The multi-wave signal generator is designed based on program-mable logical component CPLDThe VHDL programming realization and the MAX+ plus II development platform. Besides the cryst
5、al oscillator and the A/D transformation，the entire system completely integrates on the CPLD chipThe multi-wave signal generator may output the sine-wave，the triangle-wave，the square-waveThen downloaded under the situation which the entire system hardware connects do not change， and finally output t
6、he special profile which user needsThe multi-wave signal generator generates wave which the conventional function signal generators cant makeMoreover because of the programmable reset feature of the CPLD，the generator can change the wave data conveniently and practice easily The whole design realizes by the VHDL programmerIts design process has simple feature，easy modification and high transportation Keywords：Signal Generator Design；Three-phase；VHDL；CPLD；MAX+ plus II 毕业论文 目 录
