基于CPLD的三相多波形函数发生器资料

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：信号发生器设计；三相；VHDL；CPLD；MAX+ plus IIABSTRACTDirect digital frequency synthesize(DDFS) is a recently and rapidly developed technology which features high frequency resolution．This paper briefly introduces the basic principle of DDS. The basic principle and performance of CPLD chip ． Then it mainly describes how to use CPLD chip to design a function generator of high accuracy．The principle of three-phase multi-signal generator based on CPLD and DDS technology is introduced．Based on these，the modules of CPLD design are given．The multi-wave signal generator is designed based on program-mable logical component CPLD ． The VHDL programming realization and the MAX+ plus II development platform. Besides the crystal oscillator and the A/D transformation ， the entire system completely integrates on the CPLD chip．The multi-wave signal generator may output the sine-wave，the triangle-wave，the square-wave．Then downloaded under the situation which the entire system hardware connects do not change，and finally output the special profile which user needs ． The multi-wave signal generator generates wave which the conventional function signal generators can’t make．Moreover 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 programmer．Its design process has simple feature，easy modification and high transportation．Keywords：Signal Generator Design；Three-phase；VHDL；CPLD；MAX+ plus II目 录1 引 言..................................................................................................................................12 基于 CPLD 的三相多波形函数发生器设计.......................................................................32.1 波形发生器系统的设计方法及其技术指标.............................32.1.1 设计方式概述.................................................................................................32.1.2 三相函数多波形发生器技术指标................................................................52.1.3 三相波形发生器设计方法概述.....................................................................52.2 设计方案.........................................................62.2.1 三相函数发生器设计原理...