基于DDS的精密正弦信号发生器的设计
基于DDS的精密正弦信号发生器的设计
摘 要
本设计采用了直接数字频率合成（DDS）技术来实现。侧重叙述了用FPGA来完成直接数字频率合成器(DDS)的设计，DDS由相位累加器和正弦ROM查找表两个功能块组成，其中ROM查找表由兆功能模块LPM_ROM来实现。而通过设定不同的累加器初值(K1)和初始相位值(K2)，可以调节两路相同频率正弦信号之间的相位差，从而产生数字式的频率、相位和幅值可调的精密正弦波信号，最后通过MAX+PLUSII演示仿真结果。
与传统的频率合成方法相比，DDS合成信号具有频率切换时间短、频率分辨率高、相位变化连续等诸多优点。使用单片机灵活的控制能力与FPGA器件的高性能、高集成度相结合，可以克服传统DDS设计中的不足，从而设计开发出性能优良的DDS系统。
关键字 单片机 DDS FPGA 正弦信号发生器
I
基于DDS的精密正弦信号发生器的设计
DDS-BASED PRECISION SINUSOIDAL
SIGNAL GENERATOR
ABSTRACT
This design uses a direct digital frequency synthesis (DDS) technologies. Described with emphasis on FPGA to complete the direct digital synthesizer (DDS) design, DDS ROM from the phase accumulator and sine lookup table composed of two functional blocks, including ROM look-up table by the function module LPM_ROM trillion to implement. The accumulator by setting different initial (K1) and the initial phase value (K2), the same frequency can be adjusted two phase difference between the sinusoidal signal, resulting in digital, frequency, phase and amplitude adjustable precision sine wave signal, the final presentation by MAX + plus II simulation results.
And compared to the traditional method of frequency synthesis, DDS synthesized signal with frequency switching time is short, high frequency resolution, phase change continuously, and many other advantages. Flexible control using microcontroller and FPGA device performance, highly integrated combination of design can overcome the deficiencies of traditional DDS to design and develop excellent performance DDS system.
KEY WORDS single chip computer DDS FPGA Sinusoidal signal generator
II
基于DDS的精密正弦信号发生器的设计
目 录
摘 要 ............................................................................................................................................ I ABSTRACT ...................................................................................................................................... II 1 绪论 ............................................................................................................................................. 1 1.1 课题背景 .................................................................................................................................. 1 1.2 研究此课题的目的和意义 ....................................................................................................... 1 1.3 本文主要研究的工作和目标 ................................................................................................... 2 2 设计方案的概述及论证 .............................................................................................................. 4 2.1 系统的性能要求 ....................................................................................................................... 4 2.2 方案论证与比较 ....................................................................................................................... 4 2.4 方案确定 .................................................................................................................................. 5 3 FPGA部分设计 .......................................................................................................................... 6 3.1 FPGA的简介 ........................................................................................................................... 6 3.2 FPGA芯片的选择 ................................................................................................................... 7 3.3 DDS原理及相关介绍 .............................................................................................................. 9 3.4 各模块发生原理 ..................................................................................................................... 10 3.4.1 正弦波发生模块原理 .......................................................................................................... 10 3.4.2 AM硬件实现原理 .............................................................................................................. 11 3.4.3 FM调制原理 ....................................................................................................................... 11 3.4.4 ASK调制原理 ..................................................................................................................... 12 3.4.5 FSK调制原理 ..................................................................................................................... 12 3.5 正弦波发生模块的实现 ......................................................................................................... 12 3.6 FPGA设计DDS电路的具体实现 ....................................................................................... 14 3.6.1 相位累加器部分 .................................................................................................................. 14 3.6.2 相位/幅度转换电路 ............................................................................................................ 14 3.6.3 波形表生成.......................................................................................................................... 15 4.系统外围电路设计....................................................................................................................... 16 4.1 系统组成框图......................................................................................................................... 16 4.2 D/A转换电路 ......................................................................................................................... 16 4.2.1 DAC0832芯片简介 ............................................................................................................ 16 4.3 滤波电路 ................................................................................................................................ 19 4.4 数码管显示电路 ..................................................................................................................... 20 4.5 键盘接口电路......................................................................................................................... 20 5 系统的计算与仿真 .................................................................................................................... 22 5.1 MAX+plusⅡ软件介绍 ........................................................................................................ 22
基于DDS的精密正弦信号发生器的设计
5.2 系统频率、相位和幅度的计算 ............................................................................................. 23 5.2 系统仿真 ................................................................................................................................ 24 6 结论 ........................................................................................................................................... 26 致 谢 ......................................................................................................................................... 27 参考文献 ......................................................................................................................................... 28 附录1 系统原理图 ......................................................................................... 29 附录2 相关模块程序设计 ......................................................................................... 30
相关推荐：
loading