ExpressPCB 是一款免費(fèi)的PCB設(shè)計(jì)軟件，簡單實(shí)使。可以畫雙層板。 Our Free PCB software is a snap to learn and use. For the first time, designing circuit boards is simple for the beginner and efficient for the professional. Our board manufacturing service makes top quality two and four layer PCBs. Use our MiniBoard service and pay only $51 for three boards (plus $8 shipping).
標(biāo)簽： ExpressPCB PCB 設(shè)計(jì)軟件
上傳時(shí)間： 2013-10-09
上傳用戶：1047385479
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(jì)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(tái)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(jì)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(jì)
上傳時(shí)間： 2013-10-28
上傳用戶：jyycc
磁芯電感器的諧波失真分析 摘 要：簡述了改進(jìn)鐵氧體軟磁材料比損耗系數(shù)和磁滯常數(shù)ηB，從而降低總諧波失真THD的歷史過程，分析了諸多因數(shù)對諧波測量的影響，提出了磁心性能的調(diào)控方向。 關(guān)鍵詞：比損耗系數(shù)， 磁滯常數(shù)ηB ，直流偏置特性DC-Bias，總諧波失真THD Analysis on THD of the fer rite co res u se d i n i nductancShi Yan Nanjing Finemag Technology Co. Ltd., Nanjing 210033 Abstract: Histrory of decreasing THD by improving the ratio loss coefficient and hysteresis constant of soft magnetic ferrite is briefly narrated. The effect of many factors which affect the harmonic wave testing is analysed. The way of improving the performance of ferrite cores is put forward. Key words: ratio loss coefficient，hysteresis constant，DC-Bias，THD 近年來，變壓器生產(chǎn)廠家和軟磁鐵氧體生產(chǎn)廠家，在電感器和變壓器產(chǎn)品的總諧波失真指標(biāo)控制上，進(jìn)行了深入的探討和廣泛的合作，逐步弄清了一些似是而非的問題。從工藝技術(shù)上采取了不少有效措施，促進(jìn)了質(zhì)量問題的迅速解決。本文將就此熱門話題作一些粗淺探討。 一、 歷史回顧 總諧波失真（Total harmonic distortion） ，簡稱THD，并不是什么新的概念，早在幾十年前的載波通信技術(shù)中就已有嚴(yán)格要求<1>。1978年郵電部公布的標(biāo)準(zhǔn)YD/Z17－78“載波用鐵氧體罐形磁心”中，規(guī)定了高μQ材料制作的無中心柱配對罐形磁心詳細(xì)的測試電路和方法。如圖一電路所示，利用LC組成的150KHz低通濾波器在高電平輸入的情況下測量磁心產(chǎn)生的非線性失真。這種相對比較的實(shí)用方法，專用于無中心柱配對罐形磁心的諧波衰耗測試。 這種磁心主要用于載波電報(bào)、電話設(shè)備的遙測振蕩器和線路放大器系統(tǒng)，其非線性失真有很嚴(yán)格的要求。 圖中 ZD —— QF867 型阻容式載頻振蕩器，輸出阻抗 150Ω， Ld47 —— 47KHz 低通濾波器，阻抗 150Ω，阻帶衰耗大于61dB， Lg88 ——并聯(lián)高低通濾波器，阻抗 150Ω，三次諧波衰耗大于61dB Ld88 ——并聯(lián)高低通濾波器，阻抗 150Ω，三次諧波衰耗大于61dB FD —— 30～50KHz 放大器， 阻抗 150Ω， 增益不小于 43 dB，三次諧波衰耗b3(0)≥91 dB, DP —— Qp373 選頻電平表，輸入高阻抗， L ——被測無心罐形磁心及線圈， C ——聚苯乙烯薄膜電容器CMO-100V-707APF±0.5%,二只。 測量時(shí)，所配用線圈應(yīng)用絲包銅電磁線SQJ9×0.12(JB661-75)在直徑為16.1mm的線架上繞制 120 匝， （線架為一格） ， 其空心電感值為 318μH（誤差1％） 被測磁心配對安裝好后，先調(diào)節(jié)振蕩器頻率為 36.6～40KHz， 使輸出電平值為+17.4 dB， 即選頻表在 22′端子測得的主波電平 （P2）為+17.4 dB，然后在33′端子處測得輸出的三次諧波電平（P3）， 則三次諧波衰耗值為：b3(+2)= P2+S+ P3 式中：S 為放大器增益dB 從以往的資料引證， 就可以發(fā)現(xiàn)諧波失真的測量是一項(xiàng)很精細(xì)的工作，其中測量系統(tǒng)的高、低通濾波器，信號源和放大器本身的三次諧波衰耗控制很嚴(yán)，阻抗必須匹配，薄膜電容器的非線性也有相應(yīng)要求。濾波器的電感全由不帶任何磁介質(zhì)的大空心線圈繞成，以保證本身的“潔凈” ，不至于造成對磁心分選的誤判。 為了滿足多路通信整機(jī)的小型化和穩(wěn)定性要求， 必須生產(chǎn)低損耗高穩(wěn)定磁心。上世紀(jì) 70 年代初，1409 所和四機(jī)部、郵電部各廠，從工藝上改變了推板空氣窯燒結(jié)，出窯后經(jīng)真空罐冷卻的落后方式，改用真空爐，并控制燒結(jié)、冷卻氣氛。技術(shù)上采用共沉淀法攻關(guān)試制出了μQ乘積 60 萬和 100 萬的低損耗高穩(wěn)定材料，在此基礎(chǔ)上，還實(shí)現(xiàn)了高μ7000～10000材料的突破，從而大大縮短了與國外企業(yè)的技術(shù)差異。當(dāng)時(shí)正處于通信技術(shù)由FDM（頻率劃分調(diào)制）向PCM（脈沖編碼調(diào)制） 轉(zhuǎn)換時(shí)期， 日本人明石雅夫發(fā)表了μQ乘積125 萬為 0.8×10 ，100KHz）的超優(yōu)鐵氧體材料<3>，其磁滯系數(shù)降為優(yōu)鐵
上傳時(shí)間： 2013-12-15
上傳用戶：天空說我在
The data plane of the reference design consists of a configurable multi-channel XBERT modulethat generates and checks high-speed serial data transmitted and received by the MGTs. Eachchannel in the XBERT module consists of two MGTs (MGTA and MGTB), which physicallyoccupy one MGT tile in the Virtex-4 FPGA. Each MGT has its own pattern checker, but bothMGTs in a channel share the same pattern generator. Each channel can load a differentpattern. The MGT serial rate depends on the reference clock frequency and the internal PMAdivider settings. The reference design can be scaled anywhere from one channel (two MGTs)to twelve channels (twenty-four MGTs).
標(biāo)簽： RocketIO Virtex XAPP 713
上傳時(shí)間： 2013-12-25
上傳用戶：jkhjkh1982
基于通用集成運(yùn)算放大器，利用MASON公式設(shè)計(jì)了一個(gè)多功能二階通用濾波器，能同時(shí)或分別實(shí)現(xiàn)低通、高通和帶通濾波，也能設(shè)計(jì)成一個(gè)正交振蕩器。電路的極點(diǎn)頻率和品質(zhì)因數(shù)能夠獨(dú)立、精確地調(diào)節(jié)。電路使用4個(gè)集成運(yùn)放、2個(gè)電容和11個(gè)電阻，所有集成運(yùn)放的反相端虛地。利用計(jì)算機(jī)仿真電路的通用濾波功能、極點(diǎn)頻率和品質(zhì)因數(shù)的獨(dú)立控制和正交正弦振蕩，從而證明該濾波器正確有效。 Abstract: A new multifunctional second-order filter based on OPs was presented by MASON formula. Functions， such as high-pass， band-pass， low-pass filtering， can be realized respectively and simultaneously， and can become a quadrature oscillator by modifying resistance ratio. Its pole angular frequency and quality factor can be tuned accurately and independently. The circuit presented contains four OPs， two capacitors， and eleven resistances， and inverting input of all OPs is virtual ground. Its general filtering， the independent control of pole frequency and quality factor and quadrature sinusoidal oscillation were simulated by computer， and the result shows that the presented circuit is valid and effective.
標(biāo)簽： MASON 多功能 二階 濾波器設(shè)計(jì)
上傳時(shí)間： 2013-10-09
上傳用戶：13788529953
在Multisim 10軟件環(huán)境下，設(shè)計(jì)一種由運(yùn)算放大器構(gòu)成的精確可控矩形波信號發(fā)生器，結(jié)合系統(tǒng)電路原理圖重點(diǎn)闡述了各參數(shù)指標(biāo)的實(shí)現(xiàn)與測試方法。通過改變RC電路的電容充、放電路徑和時(shí)間常數(shù)實(shí)現(xiàn)了占空比和頻率的調(diào)節(jié)，通過多路開關(guān)投入不同數(shù)值的電容實(shí)現(xiàn)了頻段的調(diào)節(jié)，通過電壓取樣和同相放大電路實(shí)現(xiàn)了輸出電壓幅值的調(diào)節(jié)并提高了電路的帶負(fù)載能力，可作為頻率和幅值可調(diào)的方波信號發(fā)生器。Multisim 10仿真分析及應(yīng)用電路測試結(jié)果表明，電路性能指標(biāo)達(dá)到了設(shè)計(jì)要求。 Abstract: Based on Multisim 10， this paper designed a kind of rectangular-wave signal generator which could be controlled exactly composed of operational amplifier， the key point was how to implement and test the parameter indicators based on the circuit diagram. The duty and the frequency were adjusted by changing the time constant and the way of charging and discharging of the capacitor， the width of frequency was adjusted by using different capacitors provided with multiple switch， the amplitude of output voltage was adjusted by sampling voltage and using in-phase amplifier circuit，the ability of driving loads was raised， the circuit can be used as squarewave signal generator whose frequency and amplitude can be adjusted. The final simulation results of Multisim 10 and the tests of applicable circuit show that the performance indicators of the circuit meets the design requirements.
標(biāo)簽： Multisim 矩形波 信號發(fā)生器 仿真
上傳時(shí)間： 2014-01-21
上傳用戶：shen007yue
The TapiComm sample uses both the Telephony API and the Win32 Communications API to demonstrate one way to implement a very simple TTY application. While the user interface and TTY emulation are very rudimentary, the TAPI and comm modules are fairly complete.
標(biāo)簽： Communications demonstrate API Telephony
上傳時(shí)間： 2014-12-07
上傳用戶：chenxichenyue
* This function positions the cursor at the specified * x,y coordinate. It uses the ANSI standard ESCAPE * * sequence to produce the desired effect. Its not the * * fastest way to position the cursor, but perhaps the * * most portable. *
標(biāo)簽： the coordinate positions specified
上傳時(shí)間： 2015-02-24
上傳用戶：chenjjer
This software was done in part for a textbook on AI I ve written called _The Basis of AI_ (tentative title, subject to change but not if I get my way). For details see: http://www.mcs.com/~drt/basisofai.html
標(biāo)簽： tentative software textbook written
上傳時(shí)間： 2015-03-30
上傳用戶：cxl274287265
手機(jī)文件瀏覽器 Here are the sources to SMan v1.2c 1.2 is a major jump from v1.1. You will see this from the way the code has been restructured into multiple files. It also supports flip closed. However, to my chagrin, I made the mistake of assuming there will only be one flip closed view. :( That s changed in v1.3 :) 1.3 supports multiple flip closed views that can be easily added into SMan.
標(biāo)簽： from 1.2 the sources
上傳時(shí)間： 2015-03-31
上傳用戶：彭玖華
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