摘 要
目前，基于直接数字频率合成(Direct Digital Frequency Synthesis简称DDS)技术的任意波形发生器在设计上多采用FPGA结合微处理器芯片的形式。DDS部分功能由FPGA来实现，微处理器芯片用于完成控制功能，这种结构电路复杂，开发周期长，系统的软硬件升级也存在困难。可编程片上系统（SOPC）设计是一个崭新的、富有生机的嵌入式系统设计方向，嵌入式集成化设计正成为电子领域发展的一个重要方向。本文利用SOPC技术研究在单片FPGA上实现任意波形发生器的可行性。
论文以Altera公司的EP1C6Q240C6芯片为SOPC系统的载体，把任意波形发生器的DDS模块集成到单片FPGA芯片内部，设计了能够输出正弦波、方波、锯齿波等波形的任意波形发生器。
文中首先探讨了DDS的工作原理，然后在对任意波形发生器进行需求分析的基础上，确定了任意波形发生器的总体方案，最后，对实验结果进行了分析，并提出了改进意见。
实验结果表明：所设计的基于DDS的任意波形发生器能够实现规则波和任意波形的输出，波形性能达到了设计要求；可以用在要求波形连续平滑输出的特殊场合，解决了目前的任意波形发生器所存在的这一问题；采用SOPC 技术在单片FPGA上实现任意波形发生器是可行的，可大大减化系统电路，具有集成度高、稳定性好和扩展性强等优点。
关键词：任意波形发生器，FPGA，SOPC，DDS，QuartusⅡ，波形数据ROM
The ACTUALIZE OF SIGNAL GENERATOR ON FPGA BASED ON DDS
ABSTRACT
At the present time, the structure of FPGA(Field Programmable Gate Array)combining with microprocessor chip is frequently adopted in the design of the AWG(Arbitrary Waveform Generator) based on DDS(Direct Digital Frequency Synthesis).DDS module is realized in FPGA and the control function is finished by microprocessor. That structure has such defects as complicated hardware circuit, long developing period and difficult upgrade in both software and hardware. The design of SOPC(System on a Programmable Chip) is a piece of new and vital research field for embedded system. At the same time, embedded and integrated design is becoming an important developmental orientation in electron field. This paper intended to study the feasibility of realizing Arbitrary Waveform Generator in single FPGA chip by adopting SOPC technique.
In this paper, the EP1C6Q240C6 chip produced by Altera Ltd is used as carrier of SOPC, the DDS module is integrated into single FPGA chip, the finished Arbitrary Waveform Generator can output sine waveform, square waveform, saw tooth waveform and so on
Firstly, the DDS working theory is discussed, secondly, the general design scheme of AWG is given on the base of making requirement analysis finally ,the experimental results will be analyzed and the concerning improving advice was given.
The experimental result indicates that AWG based on DDS can output regular waveform and arbitrary waveform, which meets the designed requirement. The adoption of SOPC in the design of AWG is feasible, which enormously simplifies the system’s circuit, making the system many merits like high integrated degree, fine stability, strong expansibility and so on.
KEY WORDS：Arbitrary Waveform Generator, Field Programmable Gate Array, System on a Programmable Chip, Direct Digital Frequency Synthesis，QuartusⅡ，waveform table
