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  • WP196-平面顯示器中的Xilinx器件

      According to CIBC World Markets, Equity Research, theFlat Panel Display (FPD) industry has achieved sufficientcritical mass for its growth to explode. Thus, it can nowattract the right blend of capital investments and R&Dresources to drive technical innovation toward continuousimprovement in view quality, manufacturing efficiency,and system integration. These in turn are sustainingconsumer interest, penetration, revenue growth, and thepotential for increasing long-term profitability for industryparticipants. CIBC believes that three essential conditionsare now converging to drive the market forward

    標簽: Xilinx 196 WP 平面顯示器

    上傳時間: 2015-01-02

    上傳用戶:小楓殘月

  • 磁芯電感器的諧波失真分析

    磁芯電感器的諧波失真分析 摘  要:簡述了改進鐵氧體軟磁材料比損耗系數和磁滯常數ηB,從而降低總諧波失真THD的歷史過程,分析了諸多因數對諧波測量的影響,提出了磁心性能的調控方向。 關鍵詞:比損耗系數, 磁滯常數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,變壓器生產廠家和軟磁鐵氧體生產廠家,在電感器和變壓器產品的總諧波失真指標控制上,進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。從工藝技術上采取了不少有效措施,促進了質量問題的迅速解決。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中就已有嚴格要求<1>。1978年郵電部公布的標準YD/Z17-78“載波用鐵氧體罐形磁心”中,規定了高μQ材料制作的無中心柱配對罐形磁心詳細的測試電路和方法。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生的非線性失真。這種相對比較的實用方法,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、電話設備的遙測振蕩器和線路放大器系統,其非線性失真有很嚴格的要求。  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 ——并聯高低通濾波器,阻抗 150Ω,三次諧波衰耗大于61dB Ld88 ——并聯高低通濾波器,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,所配用線圈應用絲包銅電磁線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,先調節振蕩器頻率為 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, 就可以發現諧波失真的測量是一項很精細的工作,其中測量系統的高、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,阻抗必須匹配,薄膜電容器的非線性也有相應要求。濾波器的電感全由不帶任何磁介質的大空心線圈繞成,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的小型化和穩定性要求, 必須生產低損耗高穩定磁心。上世紀 70 年代初,1409 所和四機部、郵電部各廠,從工藝上改變了推板空氣窯燒結,出窯后經真空罐冷卻的落后方式,改用真空爐,并控制燒結、冷卻氣氛。技術上采用共沉淀法攻關試制出了μQ乘積 60 萬和 100 萬的低損耗高穩定材料,在此基礎上,還實現了高μ7000~10000材料的突破,從而大大縮短了與國外企業的技術差異。當時正處于通信技術由FDM(頻率劃分調制)向PCM(脈沖編碼調制) 轉換時期, 日本人明石雅夫發表了μQ乘積125 萬為 0.8×10 ,100KHz)的超優鐵氧體材料<3>,其磁滯系數降為優鐵

    標簽: 磁芯 電感器 諧波失真

    上傳時間: 2013-12-15

    上傳用戶:天空說我在

  • OSERL (Open SMPP Erlang Library) is an erlang implementation of the Short Message Peer to Peer proto

    OSERL (Open SMPP Erlang Library) is an erlang implementation of the Short Message Peer to Peer protocol, covering the entire specification (version 5.0). Forward and backward compatibilities guidelines were adopted.

    標簽: Peer implementation Library Message

    上傳時間: 2013-12-29

    上傳用戶:dengzb84

  • BIND 9 dynamic DNS webmin module. This module supports both static and dynamic zones, and IPv4 and I

    BIND 9 dynamic DNS webmin module. This module supports both static and dynamic zones, and IPv4 and IPv6 addressing in both forward and reverse zones.

    標簽: dynamic module and supports

    上傳時間: 2015-02-28

    上傳用戶:來茴

  • 基于Fase 4 RDF/RSS語法分析器

    基于Fase 4 RDF/RSS語法分析器,Feed是向智能信息和消息檢索代理邁出的第一步。它使用一個普通文本文件作為存儲,而沒有使用任何種類的數據庫,應該可以在任何支持PHP的站點工作

    標簽: Fase RDF RSS 語法分析器

    上傳時間: 2013-12-30

    上傳用戶:klin3139

  • Rotating shafts experience a an elliptical motion called whirl. It is important to decompose this mo

    Rotating shafts experience a an elliptical motion called whirl. It is important to decompose this motion into a forward and backward whil orbits. The current function makes use of two sensors to generate a bi-directional spectrogram. The method can be extended to any time-frequency distribution % % compute the forward/backward Campbell/specgtrogram % % INPUT: % y (n x 2) each column is measured from a different sensor % /////// % __ % |s1| y(:,1) % |__| % __ % / \ ________|/ % | | | s2 |/ y(:,2) % \____/ --------|/ % % Fs Sampling frequnecy % % OUTPUT: % B spectrogram/Campbel diagram % x x-axis coordinate vector (time or Speed) % y y-axis coordinate vector (frequency [Hz])

    標簽: experience elliptical decompose important

    上傳時間: 2015-06-23

    上傳用戶:372825274

  • This book is about the management of business processes. This is certainly not a new topic. Since t

    This book is about the management of business processes. This is certainly not a new topic. Since the beginning of the Industrial Revolution, it has been written about from every possible point of view—economic, sociological, psychological, accountancy, mechanical engineering and business administration. In this book, we examine the management of business processes from the perspective of computing, or—to put it more broadly—of information technology. The reason is that information technology has made huge leaps forward in recent years, resulting in the creation of completely new ways of organizing business processes. The development of generic software packages for managing business processes—so-called workflow management systems (WFMS)—is particularly important in this respect.

    標簽: This management certainly processes

    上傳時間: 2013-11-29

    上傳用戶:shus521

  • JavaTV Program source code Need to play Windows Media files and streams, mpeg4 video or DVDs in j

    JavaTV Program source code Need to play Windows Media files and streams, mpeg4 video or DVDs in java? Access WDM capture devices? Control a firewire DVCam? Then maybe this can help you. dsj is an ongoing project to provide a java wrapper around Microsoft s DirectShow API. It offers a set of high level classes that give java easy access to functionality widely missed by java programmers and also lets you dive deeper into the interiors of Windows core api for 2D media. On the java side dsj tries to keep things open as possible - you may use it standalone or let it feed data into JMF or other APIs.

    標簽: Program Windows streams JavaTV

    上傳時間: 2013-12-17

    上傳用戶:TF2015

  • Our approach to understanding mobile learning begins by describing a dialectical approach to the de

    Our approach to understanding mobile learning begins by describing a dialectical approach to the development and presentation of a task model using the sociocognitive engineering design method. This analysis synthesises relevant theoretical approaches. We then examine two field studies which feed into the development of the task model.

    標簽: approach understanding dialectical describing

    上傳時間: 2014-11-28

    上傳用戶:comua

  • 《JSP網絡編程從基礎到實踐》的實例代碼目錄中包含了前10章的所有實例的源代碼

    《JSP網絡編程從基礎到實踐》的實例代碼目錄中包含了前10章的所有實例的源代碼,實例名稱及其所處章節如下: 第1章 JSP技術概述 實例1 第一個JSP頁面 第3章 Web開發基礎 實例2 HTML與JavaScript交互示例 第4章 JSP語法 實例3 JSP程序的基本結構 實例4 簡單數據類型綜合應用實例 實例5 包裝類綜合應用實例 實例6 數組應用實例 實例7 字符截取程序示例 實例8 查找字符串程序示例 實例9 StringBuffer綜合應用程序示例 實例10 日期數據應用示例 實例11 算術表達式綜合運用實例 實例12 switch語句示例 實例13 循環應用綜合實例 實例14 一個簡單的計數器 實例15 include指令應用示例 實例16 forward應用程序示例 實例17 param應用程序示例 實例18 plugin應用程序示例 實例19 中文字符處理程序示例 第5章 JSP的內置對象 實例20 request常用方法的應用 實例21 獲得表單數據 實例22 頁面重定向程序示例 實例23 定時刷新頁面程序示例 實例24 記住會話的用戶名 實例25 猜字母游戲 實例26 網站計數器

    標簽: JSP 網絡編程 實踐 代碼

    上傳時間: 2013-12-06

    上傳用戶:bruce

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