【正文】 唐 山 學(xué) 院 畢 業(yè) 設(shè) 計(jì) 設(shè)計(jì)題目： 基于 DDS 技術(shù)的信號(hào)發(fā)生器的設(shè)計(jì)與實(shí)現(xiàn) 系 別： 信息工程系 班 級(jí)： 姓 名： 指 導(dǎo) 教 師： 2021 年 6 月 10 日 基于 DDS 技術(shù)的信號(hào)發(fā)生器的設(shè)計(jì)與實(shí)現(xiàn) 摘 要 DDS 是直接數(shù) 字式頻率合成器（ Direct Digital Synthesizer）的英文縮寫。與傳統(tǒng)的頻率合成器相比， DDS 具有低成本、低功耗、高分辨率和快速轉(zhuǎn)換時(shí)間等優(yōu)點(diǎn)，廣泛使用在電信與電子儀器領(lǐng)域，是實(shí)現(xiàn)設(shè)備全數(shù)字化的一個(gè)關(guān)鍵技術(shù)。 本設(shè)計(jì)采用單片機(jī)為核心處理器，利用鍵盤輸入信號(hào)的參數(shù)，控制 DDS 的AD9850 模塊產(chǎn)生信號(hào)，信號(hào)的參數(shù)在 LCD1602 上顯示，完成正弦信號(hào)和方波信號(hào)的輸出，用示波器輸出驗(yàn)證。 DDS 是一種全數(shù)字化的頻率合成器，由相位累加器、波形 ROM、 D/A 轉(zhuǎn)換器和低通濾波器構(gòu)成。時(shí)鐘頻率給定后，輸 出信號(hào)的頻率取決于頻率控制字，頻率分辨率取決于累加器位數(shù)，相位分辨率取決于 ROM 的地址線位數(shù)，幅度量化噪聲取決于 ROM 的數(shù)據(jù)位字長(zhǎng)和 D/A 轉(zhuǎn)換器位數(shù)。與傳統(tǒng)的頻率合成方法相比， DDS 合成信號(hào)具有頻率切換時(shí)間短、頻率分辨率高、相位變化連續(xù)等諸多優(yōu)點(diǎn)。使用單片機(jī)靈活的控制能力與 AD9850 的高性能、高集成度相結(jié)合，可以克服傳統(tǒng) DDS 設(shè)計(jì)中的不足，從而設(shè)計(jì)開發(fā)出性能優(yōu)良的信號(hào)發(fā)生器系統(tǒng)。 關(guān)鍵詞： 單片機(jī) 直接數(shù)字頻率合成 AD9850 DDS Design and Implementation of the Signal Generator Based on DDS Technology Abstract DDS is Direct Digital frequency Synthesizer (Direct Digital Synthesizer) English abbreviations. Compared with the traditional frequency synthesizer, with low cost, DDS low power consumption, high resolution and fast converting speed time and so on, widely used in telemunications and electronic instruments field, is to realize equipment full digital a key technology. This design uses the single chip processor as the core, using a keyboard input signal parameters, control of DDS AD9850 module produce signals, the signal parameters in LCD1602 show that the plete sine signal and square wave signal output, the output with an oscilloscope validation. DDS is A full digital frequency synthesizer, by phase accumulators, waveform ROM, D/A converter and low pass filter position. The clock frequency after A given, the output depends on the frequency of the signal frequency control word, the frequency resolution depends on accumulators digits, phase resolution depends on the ROM address line digits, amplitude quantization noise depends on the ROM data A word length and D/A converter digits. And the frequency of the traditional method than the synthesis, DDS synthesis signal has a frequency switching frequency of short time, high resolution and continuous phase changes, and many other advantages. Using single chip microputer control of the flexible ability and high performance, high level of integration of the AD9850 bination, can overe the disadvantage of the traditional DDS design, to design the developed good performance of signal generator system. Key word: MCU。 direct digital frequency synthesis。AD9850。DDS 目 錄 1 引言 ................................................................................................................................ 1 2 DDS 概要 ......................................................................................................................... 2 DDS 介紹 .................................................................................................................. 2 DDS 結(jié)構(gòu) ......................................................................................................... 2 DDS 函數(shù)發(fā)生器 ............................................................................. 3 DDS 數(shù)學(xué)原理 .......................................................................................................... 5 3 總體設(shè)計(jì)方案 ................................................................................................................ 8 系統(tǒng)設(shè)計(jì)原理 .......................................................................................................... 8 總體設(shè)計(jì)框圖 .......................................................................................................... 8 4 系統(tǒng)硬件模塊的組成 .................................................................................................... 9 單片機(jī)控制模塊 ...................................................................................................... 9 STC89C52 主要性能 ....................................................................................... 9 STC89C52 功能特性描述 ............................................................................... 9 時(shí)鐘電路 ....................................................................................................... 11 復(fù)位電路 ........................................................................................................ 11 AD9850 模塊 ....................................................................................................... 12 AD9850 簡(jiǎn)介 .................................................................................................. 12 AD9850 的控制字與控制時(shí)序 ...................................................................... 14 單片機(jī)與 AD9850 的接口 ............................................................................. 15 濾波電路設(shè)計(jì) ........................................................................................................ 15 鍵盤控制模塊 ........................................................................................................ 16 LCD 顯示模塊 ........................................................................................................ 16 液晶顯示器顯示原理 .................................................................................... 16 1602LCD 引腳與時(shí)序 ................................................................................... 17 A/D 轉(zhuǎn)換模塊 ......................................................................................................... 20 5 軟件設(shè)計(jì)與調(diào)試 .......................................................................................................... 21 程序流程圖 ............................................................................................................ 21 軟件調(diào)試 ................................................................................................................. 22 kei