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
上傳時間： 2013-12-15
上傳用戶：天空說我在
This document provides practical, common guidelines for incorporating PCI Express interconnect layouts onto Printed Circuit Boards (PCB) ranging from 4-layer desktop baseboard designs to 10- layer or more server baseboard designs. Guidelines and constraints in this document are intended for use on both baseboard and add-in card PCB designs. This includes interconnects between PCI Express devices located on the same baseboard (chip-to-chip routing) and interconnects between a PCI Express device located “down” on the baseboard and a device located “up” on an add-in card attached through a connector. This document is intended to cover all major components of the physical interconnect including design guidelines for the PCB traces, vias and AC coupling capacitors, as well as add-in card edge-finger and connector considerations. The intent of the guidelines and examples is to help ensure that good high-speed signal design practices are used and that the timing/jitter and loss/attenuation budgets can also be met from end-to-end across the PCI Express interconnect. However, while general physical guidelines and suggestions are given, they may not necessarily guarantee adequate performance of the interconnect for all layouts and implementations. Therefore, designers should consider modeling and simulation of the interconnect in order to ensure compliance to all applicable specifications. The document is composed of two main sections. The first section provides an overview of general topology and interconnect guidelines. The second section concentrates on physical layout constraints where bulleted items at the beginning of a topic highlight important constraints, while the narrative that follows offers additional insight.
上傳時間： 2014-01-24
上傳用戶：s363994250
Accurate measurement of the third order intercept pointfor low distortion IC products such as the LT5514 requirescertain precautions to be observed in the test setup andtesting procedure. The LT5514 linearity performance ishigh enough to push the test equipment and test set-up totheir limits. A method for accurate measurement of thirdorder intermodulation products, IM3, with standard testequipment is outlined below.It is also important to correctly interpret the LT5514specification with respect to ROUT, and the impact ofdemo-board transmission-line termination loss whenevaluating the linearity performance, as explained in theLT5514 Datasheet and in Note 1 of this document.
上傳時間： 2013-11-14
上傳用戶：l254587896
SL811開發資料_包含源程序_電路圖_芯片資料:SL811HS Embedded USB Host/Slave Controller.The SL811HS is an Embedded USB Host/Slave Controller capable of communicate with either full-speed or low-speed USB peripherals. The SL811HS can interface to devices such as microprocessors, microcontrollers, DSPs, or directly to a variety of buses such as ISA, PCMCIA, and others. The SL811HS USB Host Controller conforms to USB Specification 1.1.The SL811HS USB Host/Slave Controller incorporates USB Serial Interface functionality along with internal full-/low-speed transceivers.The SL811HS supports and operates in USB full-speed mode at 12 Mbps, or at low-speed 1.5-Mbps mode.The SL811HS data port and microprocessor interface provide an 8-bit data path I/O or DMA bidirectional, with interrupt support to allow easy interface to standard microprocessors or microcontrollers such as Motorola or Intel CPUs and many others. Internally,the SL811HS contains a 256-byte RAM data buffer which is used for control registers and data buffer.The available package types offered are a 28-pin PLCC (SL811HS) and a 48-pin TQFP package (SL811HST-AC). Both packages operate at 3.3 VDC. The I/O interface logic is 5V-tolerant.
上傳時間： 2013-12-22
上傳用戶：a82531317
Title: STL Tutorial and Reference Guide: C++ Programming with the Standard Template Library (2nd Edition) Author: David R. Musser / Gillmer J. Derge / Atul Saini / Gilmer J. Derge Publisher: Addison-Wesley Page: 560 Edition: 2nd edition (March 27, 2001) Format: PDF Summary: The Standard Template Library was created as the first library of genetic algorithms and data structures, with four ideas in mind: generic programming, abstractness without loss of efficiency, the Von Neumann computation model, and value semantics. This guide provides a tutorial, a description of each element of the library, and sample applications. The expanded second edition includes new code examples and demonstrations of the use of STL in real-world C++ software development it reflects changes made to STL for the final ANSI/ISO C++ language standard.
標簽： Programming Reference Standard Template
上傳時間： 2014-01-19
上傳用戶：netwolf
THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.
標簽： PROVIDED INFORMATION THE MICROSOFT
上傳時間： 2014-01-06
上傳用戶：skhlm
英文版,pdf格式。 詳細說明： Title: STL Tutorial and Reference Guide: C++ Programming with the Standard Template Library (2nd Edition) URL: http://www.amazon.com/exec/obidos/tg/detail/-/0201379236/ ISBN: 0201379236 Author: David R. Musser / Gillmer J. Derge / Atul Saini / Gilmer J. Derge Publisher: Addison-Wesley Page: 560 Edition: 2nd edition (March 27, 2001) Catalog: C++ Format: PDF Size: 3.8M Supplier: December Summary: The Standard Template Library was created as the first library of genetic algorithms and data structures, with four ideas in mind: generic programming, abstractness without loss of efficiency, the Von Neumann computation model, and value semantics. This guide provides a tutorial, a description of each element of the library, and sample applications. The expanded second edition includes new code examples and demonstrations of the use of STL in real-world C++ software development it reflects changes made to STL for the final ANSI/ISO C++ language standard.
標簽： Programming Reference Standard Tutorial
上傳時間： 2015-09-02
上傳用戶：Breathe0125
* * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE * GOODS OR SERVICES LOSS OF USE, DATA, OR PROFITS OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH D
標簽： WARRANTIES SOFTWARE PROVIDED EXPRESS
上傳時間： 2013-12-20
上傳用戶：sxdtlqqjl
TION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. WARNING! Although the AD7008 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
標簽： Electrostatic electrostatic discharge sensitive
上傳時間： 2014-01-12
上傳用戶：2467478207
// Copyright (c), Philips Semiconductors Gratkorn // (C)PHILIPS Electronics N.V.2000 // All rights are reserved. // Philips reserves the right to make changes without notice at any time. // Philips makes no warranty, expressed, implied or statutory, including but // not limited to any implied warranty of merchantibility or fitness for any //particular purpose, or that the use will not infringe any third party patent, // copyright or trademark. Philips must not be liable for any loss or damage // arising from its use.
標簽： Semiconductors Electronics Copyright Gratkorn
上傳時間： 2016-02-04
上傳用戶：xuanjie
