摘 要
目前，基于直接數字頻率合成(Direct Digital Frequency Synthesis簡稱DDS)技術的任意波形發生器在設計上多采用FPGA結合微處理器芯片的形式。DDS部分功能由FPGA來實現，微處理器芯片用于完成控制功能，這種結構電路復雜，開發周期長，系統的軟硬件升級也存在困難。可編程片上系統（SOPC）設計是一個嶄新的、富有生機的嵌入式系統設計方向，嵌入式集成化設計正成為電子領域發展的一個重要方向。本文利用SOPC技術研究在單片FPGA上實現任意波形發生器的可行性。
論文以Altera公司的EP1C6Q240C6芯片為SOPC系統的載體，把任意波形發生器的DDS模塊集成到單片FPGA芯片內部，設計了能夠輸出正弦波、方波、鋸齒波等波形的任意波形發生器。
文中首先探討了DDS的工作原理，然后在對任意波形發生器進行需求分析的基礎上，確定了任意波形發生器的總體方案，最后，對實驗結果進行了分析，并提出了改進意見。
實驗結果表明：所設計的基于DDS的任意波形發生器能夠實現規則波和任意波形的輸出，波形性能達到了設計要求；可以用在要求波形連續平滑輸出的特殊場合，解決了目前的任意波形發生器所存在的這一問題；采用SOPC 技術在單片FPGA上實現任意波形發生器是可行的，可大大減化系統電路，具有集成度高、穩定性好和擴展性強等優點。
關鍵詞：任意波形發生器，FPGA，SOPC，DDS，QuartusⅡ，波形數據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
