【正文】 hing is often the most difficult to open one39。t lose your life and the life, respectively is: the former is a we experienced cannot escape in a day finally will last minute, while the latter is our persistent, we want to cherish the memory of those people and things. 14, learn to smile, learn to strong, the world you know so many people, so many people and you are, you cannot change also can39。 but the most important is good to cherish their own. 21, life, select the plex, is to choose the pain。s two laws, doing practical play highway. 2020 October 18, the Central Committee of the Communist Party of China promulgated the implementation of the the probity of the Communist Party of China selfdiscipline criterion and Chinese Communist Party discipline and punishment regulations. We Heyuan male passersby to respond positively to the call of the Central Committee of the party, earnestly anize the study party two regulations, truly grasp the essence and gist, and in their respective positions, to hold the bottom line of the discipline, build a strong ideological line of defense, with the courage to play, the courage to fight tough and fearless spirit, at the crucial moment well to plete the task, with practical action to test the study and implement effect Because of discipline in the * * * * * * * * * * * story. Here, let me to cast a brick to attract jade, speak about our highway. Highway line section of the road surface transformation project, last year towards the country 多功能信號發(fā)生器 25 seized will be seized one of the items. To plete this arduous task, as a project management office director Comrade, keep in mind from the Communist Party membership, recognize and identify the bottom line, strict management, and strict adherence to the quality of the project. He not only set an example, honesty and selfdiscipline, but also requires the management of all the members of the ., do not eat the construction unit one meal, do not accept the construction unit a ceremony. In this way, they didn39。 difficult to myself to move away the heart of stone head. Leave time to spend with her, often reflect my heart, so as to remove your heart of stone. 24, everything does not have to be demanding, e to, everything does not have to care about, over the past。 to be alive, you will have trouble. Life is the most afraid of what all want to care about, but also what all grasp is not firm, without scenery, separated populations, such as not to desire, all docked in the fate of the end. Why is too rigid, the natural, to go stay not to live, let go of obsession, revel is 20, if the fate of the broken Hopes of sailing, please don39。 no matter how many grievances, how unfortable, and ultimately to heal themselves or their own, others may got you to fort, but never know your heart is how wanjianchuanxin. 12, ma39。 life happy and worry, all is you of life attitude, optimistic, good luck。t always take everything back to things, and don39。縱向 。 FR11 M ΩR220kΩV C C1 2 VV D D12V 圖 36 峰 峰值檢測電路 多功能信號發(fā)生器 10 軟件實現(xiàn) 系統(tǒng)以單片機(jī)為控制器，采用 C 語言對單片機(jī)進(jìn)行編程。 交流電源在正半周的一段時間內(nèi) , 通過二極管對電容充電 ， 使電容上的電壓逐漸趨近于峰值電壓。 ADC12 模塊中由以下部分組成：輸入的 16 路模擬開關(guān) ,ADC 內(nèi)部電壓參考源， ADC12 內(nèi)核， ADC時鐘源部分，采集與保持 /觸發(fā)源部分， ADC 數(shù)據(jù)輸出部分， ADC 控制寄存器等組成。其主要部分是一塊與顯示器表面非常配合的電阻薄膜屏，這是一種多層的復(fù)合薄膜，它以一層玻璃或硬塑料平板作為基層，表面涂有一層透明的金屬氧化物 (ITO)導(dǎo)電層，上面再蓋有一層外表面硬化處理、光滑防劃傷的塑料層 (其內(nèi)表面也涂有一層 ITO 涂層 ),在他們之間有許多細(xì)小的（大約 1/1000 英寸）透明間隔點把兩層 ITO 導(dǎo)電層隔開絕緣。 范圍的一個相位點。 鑒于本系統(tǒng)的 擴(kuò)展要求，我們采用 LCD 液晶作為我們的顯示模塊。 結(jié)合本系統(tǒng)，權(quán)衡兩方案利弊，我們最后決定采用方案一作為輸入控制模塊。 圖 22 AD9850 基本結(jié)構(gòu) 多功能信號發(fā)生器 4 綜合比較以上方案，結(jié)合信號發(fā)生器產(chǎn)生的頻率穩(wěn)定度和精確度要求，我們選擇DDS 直接數(shù)字頻率合成。它是電壓控制頻率的集成芯片，失真度很低。 方案二：用 FPGA 等可編程器件作為控制模塊。 對于信號調(diào)制， 直接用電平發(fā)送容易收到干擾，而且效率也不高，我們只能用光電二極管來接收，抗干擾能力弱，如果調(diào)制，我們可以用高靈敏度的接 收 頭，里面有載波檢測電路，有抑制干擾的能力。本文介紹了 DDS(直接數(shù)字頻率合成 )的基本原理和工作特點，提出以 DDS 芯片 AD9850 芯片為核心利用 MSP430F169單片機(jī)控制 ，輔以必要的外圍電路，構(gòu)成一個輸出波形穩(wěn)定、精度較高的信號發(fā)生器。隨著電子技術(shù)的發(fā)展，對信號源的頻率穩(wěn)定度、準(zhǔn)確度以及頻譜純度提出越來越高的要求?？傮w框圖如圖 21所 示 ?；诰C合性價比，確定選擇方案一。相位累加器的最大計數(shù)長度與正弦查詢表中所存儲的相位分隔點數(shù)相同，由 于相位累加器的相位增量不同，將導(dǎo)致一周期內(nèi)的取樣點數(shù)不同，在取樣頻率 (由參考時鐘頻率決定 )不變的情況下，輸出信號的頻率也相應(yīng)變化。 輸入控制模塊比較與論證 方案一：采用觸摸液晶屏 觸摸屏在日常生活中隨處可見，不管你是觸摸電腦，還是觸摸手機(jī)都離不開觸摸屏的使用，而觸摸屏因為有堅固耐用，反應(yīng)速度快，節(jié)省空間， 能夠?qū)崿F(xiàn)更加有效的人機(jī)互動等功能 等諸多優(yōu)點，為大眾所接受。 其優(yōu)點是顯示信息非常豐富，可以很形象的顯示信號發(fā)生器的各個參數(shù)。 AD9850 的 DDS 系統(tǒng)包括相位累加器和正弦查找表，其中相位累加器由一個加法器和一個 32 位寄存器組成，相位寄存器的輸出與外部相位控制字（ 5 位）相加后作為正弦查找表的地址。 電路圖如圖 32 和 圖 33 所示 。這樣所得到光暗對比 的現(xiàn)象，叫做扭轉(zhuǎn)式向列場效應(yīng)，簡稱 TNFE多功能信號發(fā)生器 8 （ twisted nematic field effect）。 而 所采用的積分行電路的工作原理則是是將輸入電壓轉(zhuǎn)換成時間 (脈沖 寬度信號 )或頻率 (脈沖頻率 )，然后由定時器 /計數(shù)器獲得數(shù)字值。 為了避免次級輸入電阻的影響 , 可在檢測器的輸出端加一級跟隨器 (高輸入阻抗 )作為隔離級， 同時可在檢測器前加一級比較放大器，使其更 直觀。 開 始芯 片 內(nèi) 部 資 源 初 始 化L E D 初 始 化 及 開 機(jī) 界 面主 菜 單頻 率 及 參 數(shù) 設(shè) 置工 作 界 面 及 波 形 輸 出反 饋 調(diào) 節(jié)進(jìn) 入 菜 單 ？NY選 擇 波 形 類 型 圖 37 主要流程圖 多功能信號發(fā)生器 11 4 系統(tǒng)測試 主要測試用的儀器 ① TDS1002 數(shù)字示波器； ② 自制電源 ； ③ UT39A 數(shù)字萬用表 。 not to have conquered, but to have fought well. 2, the plain is the background of life. Live a plain life, give up on themselves is not a coward, but the wise answers。m afraid he turned to it as a joke to tell don39。s mouth, because words will reduce its 多功能信號發(fā)生器 20 importance。t let everyone like you, so also do not want to do. Life is too short to go crazy to love to go to waste, to chase the dream to regret. 15, when temper, a blessing to 多功能信號發(fā)生器 21 go. A wounding elegant people, the key is to control their own emotions. With the mouth is the most stupid behavior. A control negative emotions than a can take a city more powerful water flow slow, language is expensive. People spent two years of time to learn to speak, but to spend a few years time to shut up. That is a kind of ability, that is a kind of wisdom. 16, life is not perfect, sometimes, growth is not a cry, not an eyeful of tears, there is no trace of emotion, there is no gleam of hope, no desire, no action, no static, there is only one kind of downward sinking fe