PCB LAYOUT 基本規(guī)範(fàn)項(xiàng)次 項(xiàng)目 備註1 一般PCB 過板方向定義： PCB 在SMT 生產(chǎn)方向?yàn)槎踢呥^迴焊爐(Reflow), PCB 長邊為SMT 輸送帶夾持邊. PCB 在DIP 生產(chǎn)方向?yàn)镮/O Port 朝前過波焊爐(wavE Solder), PCB 與I/O 垂直的兩邊為DIP 輸送帶夾持邊.1.1 金手指過板方向定義： SMT: 金手指邊與SMT 輸送帶夾持邊垂直. DIP: 金手指邊與DIP 輸送帶夾持邊一致.2 SMD 零件文字框外緣距SMT 輸送帶夾持邊L1 需≧150 mil. SMD 及DIP 零件文字框外緣距板邊L2 需≧100 mil.3 PCB I/O port 板邊的螺絲孔(精靈孔)PAD 至PCB 板邊, 不得有SMD 或DIP 零件(如右圖黃色區(qū)).PAD
上傳時間： 2014-12-24
上傳用戶：jokey075
Abstract: Impedance mismatches in a radio-frequency (RF) electrical transmission line cause power loss andreflected energy. Voltage standing wavE ratio (VSWR) is a way to measure transmission line imperfections. Thistutorial defines VSWR and explains how it is calculated. Finally, an antenna VSWR monitoring system is shown.
標(biāo)簽： VSWR 輸電線路 精確測量 電壓駐波比
上傳時間： 2013-10-19
上傳用戶：yuanwenjiao
鎖定放大是微弱信號檢測的重要手段。基于相關(guān)檢測理論，利用開關(guān)電容的開關(guān)實(shí)現(xiàn)鎖定放大器中乘法器的功能，提出開關(guān)電容和積分器相結(jié)合以實(shí)現(xiàn)相關(guān)檢測的方法，并設(shè)計出一種鎖定放大器。該鎖定放大器將微弱信號轉(zhuǎn)化為與之相關(guān)的方波，通過后續(xù)電路得到正比于被測信號的直流電平，為后續(xù)采集處理提供方便。測量數(shù)據(jù)表明鎖定放大器前級可將10-6 A的電流轉(zhuǎn)換為10-1 V的電壓，后級通過帶通濾波器級聯(lián)可將信號放大1×105倍。該方法在降低噪聲的同時，可對微弱信號進(jìn)行放大，線性度較高、穩(wěn)定性較好。 Abstract: Lock-in Amplifying（LIA）is one of important means for weak signal detection. Based on cross-correlation detection theory， switch in the swithched capacitor was used as multiplier of LIA， and a new method of correlation detection was proposed combining swithched capacitor with integrator. A kind of LIA was designed which can convert the weak signal to square-wavE， then DC proportional to measured signal was obtained through follow-up conditioning circuit， providing convenience for signal acquisition and processing. The measured data shows that the electric current（10-6 A） can be changed into voltage（10-1 V） by LIA， and the signal is magnified 1×105 times by cascade band-pass filter. The noise is suppressed and the weak signal is amplified. It has the advantages of good linearity and stability.
標(biāo)簽： 開關(guān)電容 鎖定放大器
上傳時間： 2013-11-29
上傳用戶：黑漆漆
數(shù)字控制的交流調(diào)速系統(tǒng)所選用的微處理器、功率器件及產(chǎn)生PWM波的方法是影響交流調(diào)速系統(tǒng)性能好壞的直接因素。在介紹了正弦脈寬調(diào)制(SPWM)技術(shù)的基礎(chǔ)上，設(shè)計了一種以8098單片機(jī)作為控制器，以智能功率模塊IPM為開關(guān)器件的變頻調(diào)速系統(tǒng)。通過軟件編程，產(chǎn)生正弦脈沖寬度調(diào)制波形來控制絕緣柵雙極晶體管的導(dǎo)通和關(guān)斷，從而達(dá)到控制異步電動機(jī)轉(zhuǎn)速的目的。實(shí)驗(yàn)結(jié)果表明，該系統(tǒng)可調(diào)頻率調(diào)電壓，穩(wěn)定度高，調(diào)速范圍寬，具有較強(qiáng)的實(shí)用價值 Abstract: AC variable speed with digital control systems used microprocessors， power devices and generate PWM wavE is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology，this paper designed variable speed system which used 8098 as a controller， intelligent power module IPM as switching device. Through software programming， resulting in sinusoidal pulse width modulation wavEform to control the insulated gate bipolar transistor turn on and off， so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation voltage， high stability， wide speed range， has a strong practical value.
標(biāo)簽： 8098 SPWM 單片機(jī) 變頻調(diào)速系統(tǒng)
上傳時間： 2013-11-14
上傳用戶：ynwbosss
介紹一種無極可調(diào)交流電子負(fù)載設(shè)計的新方法，由ATmega48單片機(jī)輸出PWM波，通過上位機(jī)設(shè)定不同的占空比控制場效應(yīng)管的通斷時間，即改變流過場效應(yīng)管的平均電流。根據(jù)電流的大小，可以等效為相應(yīng)的負(fù)載，并將采集的電流值顯示在上位機(jī)上。文中對該系統(tǒng)的軟﹑硬件設(shè)計思路作了詳細(xì)的分析，闡述了其設(shè)計原理。 Abstract: A new type electronic load is introduced.Due to ATmega48 microcomputer output PWM wavE.The different duty is set ratio through PC to control FET turn-on time.We can equivalent homologous load according the current and display the current at PC.The hardware and software designing are analysed in detail. The principle is explained and the output is also given.
標(biāo)簽： ATmega 48 單片機(jī) 交流電子
上傳時間： 2013-11-23
上傳用戶：蟲蟲蟲蟲蟲蟲
用戶程序示例教程 The Blinky project is a simple program for the LPC2138using Keil MCB2130 Microcontroller Board. It blinks the LEDs at speed according to the Potentiometer setting and prints the current seting to the Serial Port 1.In addition it generates a sine wavE with an adjustable frequency on the speaker of the board.
上傳時間： 2014-12-27
上傳用戶：hongmo
單片機(jī)原理及應(yīng)用實(shí)驗(yàn)報告:實(shí)驗(yàn)1 wavE軟件的學(xué)習(xí)應(yīng)用*.1實(shí)驗(yàn)2下載軟件的學(xué)習(xí)應(yīng)用*.2實(shí)驗(yàn)3運(yùn)算指令的應(yīng)用編程.3實(shí)驗(yàn)4 P0口輸入、輸出實(shí)驗(yàn).4實(shí)驗(yàn)5數(shù)碼管顯示5實(shí)驗(yàn)6按鍵的識別*6實(shí)驗(yàn)7計算器設(shè)計實(shí)驗(yàn)*7實(shí)驗(yàn)8中斷實(shí)驗(yàn)8實(shí)驗(yàn)9定時器/計數(shù)器實(shí)驗(yàn)9實(shí)驗(yàn)10串行口通訊實(shí)驗(yàn).10實(shí)驗(yàn)11直流電機(jī)調(diào)速實(shí)驗(yàn)*.12實(shí)驗(yàn)12 IC卡讀寫實(shí)驗(yàn)*13實(shí)驗(yàn)13 TLC2543的應(yīng)用實(shí)驗(yàn)*14實(shí)驗(yàn)14溫度測量及控制實(shí)驗(yàn)*.15附錄A 偉福仿真器系統(tǒng)概述16附錄B STC-ISP-V3.1 界面23附錄C 實(shí)驗(yàn)板.24
標(biāo)簽： 單片機(jī)原理 實(shí)驗(yàn)報告
上傳時間： 2013-11-13
上傳用戶：王小奇
在偉福集成環(huán)境下使用PICC.講述在偉福集成環(huán)境如可設(shè)置PICC, 簡單的調(diào)試步驟. 更詳細(xì)的說明請參閱偉福仿真器使用手冊.關(guān)于如何在MPLAB 下使用PICC C 語言, 請參閱Microchip 相應(yīng)的手冊. 2-1 安裝PICC將CD-ROM 裝入光驅(qū), 自動運(yùn)行程序?qū)⒆詣訂? 如果你已禁止自動運(yùn)行功能, 可以直接運(yùn)行: cd_drive:\compiler\install.exe安裝程序?qū)⒅笇?dǎo)你完成PICC 的安裝.2-2 設(shè)置偉福集成環(huán)境在偉福集成環(huán)境中, 將編譯器路徑指向PICC 所在目錄將Ｃ命令行設(shè)置為: -16F877 –G –O –Zg -c將連接命令行設(shè)置為: -16F877 –G –O -Zg其中: -16F877 為芯片型號–G –O -c 為源程序調(diào)試設(shè)置項(xiàng), 不可修改–Zg 為打開優(yōu)化你可以在命令行中加入其它控制項(xiàng)2-3 調(diào)試Ｃ語言在wavE\SAMPLES 目錄下有一個PIC C 語言的例子程序: PIC_C.PRJ.１. 打開PIC_C 項(xiàng)目.２. 編譯該項(xiàng)目(F9)３. 用F7,F8 單步調(diào)試?yán)映绦颍? 打開觀察窗口觀察變量
標(biāo)簽： PICC 集成環(huán)境
上傳時間： 2013-10-16
上傳用戶：lili123
在綜合分析諧波勵磁無刷同步發(fā)電機(jī)勵磁控制系統(tǒng)的基礎(chǔ)上,對其勵磁控制策略進(jìn)行了研究,開發(fā)了一套基于DSP( TMS320F2812) 控制的新型柴油發(fā)電機(jī)勵磁控制系統(tǒng),該系統(tǒng)采用參數(shù)自適應(yīng)模糊PID 控制勵磁,選用交流采樣方式實(shí)時檢測各信號的瞬時特性,系統(tǒng)仿真結(jié)果以及在1 臺25 kW 工頻柴油發(fā)電機(jī)上的試驗(yàn)結(jié)果證明了該控制器具有較好的電壓調(diào)節(jié)特性,系統(tǒng)穩(wěn)態(tài)和暫態(tài)性能完全滿足發(fā)電機(jī)對勵磁系統(tǒng)的要求。關(guān)鍵詞:勵磁調(diào)節(jié);模糊PID 控制;數(shù)字信號處理器;交流采樣 Abstract :According to the general analysis of the excitation cont rol system of the harmonious wavE excitation brushless synchronous generator and it s characteristics ,a new type of diesel generator excitation cont rol system based on DSP( TMS320F2812) was designed. An adaptive fuzzy PID cont rol of excitation is used in this system. To detect the t ransient characteristics of the signals in a timely manner ,AC sampling was applied.The system simulation result s and the testing result s f rom a 25 kW diesel generator (50 Hz) can prove that the voltage regulation characteristics of the excitation cont rol system are very well ,and both the steadyOstate performance and the t ransient performance of the generator are also good.Key words :excitation cont rol ;fuzzy PID cont rol ;digital signal processor (DSP) ;AC sampling
標(biāo)簽： DSP 柴油發(fā)電機(jī) 勵磁控制 系統(tǒng)研究
上傳時間： 2013-10-29
上傳用戶：fxf126@126.com
為了在CDMA系統(tǒng)中更好地應(yīng)用QDPSK數(shù)字調(diào)制方式，在分析四相相對移相（QDPSK)信號調(diào)制解調(diào)原理的基礎(chǔ)上，設(shè)計了一種QDPSK調(diào)制解調(diào)電路，它包括串并轉(zhuǎn)換、差分編碼、四相載波產(chǎn)生和選相、相干解調(diào)、差分譯碼和并串轉(zhuǎn)換電路。在MAX+PLUSⅡ軟件平臺上，進(jìn)行了編譯和波形仿真。綜合后下載到復(fù)雜可編程邏輯器件EPM7128SLC84-15中，測試結(jié)果表明，調(diào)制電路能正確選相，解調(diào)電路輸出數(shù)據(jù)與QDPSK調(diào)制輸入數(shù)據(jù)完全一致，達(dá)到了預(yù)期的設(shè)計要求。 Abstract: In order to realize the better application of digital modulation mode QDPSK in the CDMA system， a sort of QDPSK modulation-demodulation circuit was designed based on the analysis of QDPSK signal modulation-demodulation principles. It included serial/parallel conversion circuit, differential encoding circuit, four-phase carrier wavE produced and phase chosen circuit, coherent demodulation circuit, difference decoding circuit and parallel/serial conversion circuit. And it was compiled and simulated on the MAX+PLUSⅡ software platform,and downloaded into the CPLD of EPM7128SLC84-15.The test result shows that the modulation circuit can exactly choose the phase，and the output data of the demodulator circuit is the same as the input data of the QDPSK modulate. The circuit achieves the prospective requirement of the design.
標(biāo)簽： QDPSK CPLD 調(diào)制解調(diào) 電路設(shè)計
上傳時間： 2014-01-13
上傳用戶：qoovoop
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