The RT9018A/B is a high performance positive voltage regulator designed for use in applications requining very low Input voltage and very low dropout voltage at up to 3A(peak).
上传时间： 2013-10-10
上传用户：geshaowei
磁芯电感器的谐波失真分析 摘 要：简述了改进铁氧体软磁材料比损耗系数和磁滞常数ηB，从而降低总谐波失真THD的历史过程，分析了诸多因数对谐波测量的影响，提出了磁心性能的调控方向。 关键词：比损耗系数， 磁滞常数ηB ，直流偏置特性DC-Bias，总谐波失真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 近年来，变压器生产厂家和软磁铁氧体生产厂家，在电感器和变压器产品的总谐波失真指标控制上，进行了深入的探讨和广泛的合作，逐步弄清了一些似是而非的问题。从工艺技术上采取了不少有效措施，促进了质量问题的迅速解决。本文将就此热门话题作一些粗浅探讨。 一、 历史回顾 总谐波失真（Total harmonic distortion） ，简称THD，并不是什么新的概念，早在几十年前的载波通信技术中就已有严格要求<1>。1978年邮电部公布的标准YD/Z17－78“载波用铁氧体罐形磁心”中，规定了高μQ材料制作的无中心柱配对罐形磁心详细的测试电路和方法。如图一电路所示，利用LC组成的150KHz低通滤波器在高电平输入的情况下测量磁心产生的非线性失真。这种相对比较的实用方法，专用于无中心柱配对罐形磁心的谐波衰耗测试。 这种磁心主要用于载波电报、电话设备的遥测振荡器和线路放大器系统，其非线性失真有很严格的要求。 图中 ZD —— QF867 型阻容式载频振荡器，输出阻抗 150Ω， Ld47 —— 47KHz 低通滤波器，阻抗 150Ω，阻带衰耗大于61dB， Lg88 ——并联高低通滤波器，阻抗 150Ω，三次谐波衰耗大于61dB Ld88 ——并联高低通滤波器，阻抗 150Ω，三次谐波衰耗大于61dB FD —— 30～50KHz 放大器， 阻抗 150Ω， 增益不小于 43 dB，三次谐波衰耗b3(0)≥91 dB, DP —— Qp373 选频电平表，输入高阻抗， L ——被测无心罐形磁心及线圈， C ——聚苯乙烯薄膜电容器CMO-100V-707APF±0.5%,二只。 测量时，所配用线圈应用丝包铜电磁线SQJ9×0.12(JB661-75)在直径为16.1mm的线架上绕制 120 匝， （线架为一格） ， 其空心电感值为 318μH（误差1％） 被测磁心配对安装好后，先调节振荡器频率为 36.6～40KHz， 使输出电平值为+17.4 dB， 即选频表在 22′端子测得的主波电平 （P2）为+17.4 dB，然后在33′端子处测得输出的三次谐波电平（P3）， 则三次谐波衰耗值为：b3(+2)= P2+S+ P3 式中：S 为放大器增益dB 从以往的资料引证， 就可以发现谐波失真的测量是一项很精细的工作，其中测量系统的高、低通滤波器，信号源和放大器本身的三次谐波衰耗控制很严，阻抗必须匹配，薄膜电容器的非线性也有相应要求。滤波器的电感全由不带任何磁介质的大空心线圈绕成，以保证本身的“洁净” ，不至于造成对磁心分选的误判。 为了满足多路通信整机的小型化和稳定性要求， 必须生产低损耗高稳定磁心。上世纪 70 年代初，1409 所和四机部、邮电部各厂，从工艺上改变了推板空气窑烧结，出窑后经真空罐冷却的落后方式，改用真空炉，并控制烧结、冷却气氛。技术上采用共沉淀法攻关试制出了μQ乘积 60 万和 100 万的低损耗高稳定材料，在此基础上，还实现了高μ7000～10000材料的突破，从而大大缩短了与国外企业的技术差异。当时正处于通信技术由FDM（频率划分调制）向PCM（脉冲编码调制） 转换时期， 日本人明石雅夫发表了μQ乘积125 万为 0.8×10 ，100KHz）的超优铁氧体材料<3>，其磁滞系数降为优铁
上传时间： 2013-12-15
上传用户：天空说我在
介绍了以PLC为控制单元，变频器为执行单元的控制系统及其在烟支输送储存系统中的应用，并给出了系统的组成、硬件的配置及具体的实现方法。关键词 : PLC 变频器输送储存系统 Ab str ac t;T hisp aperi ntroducest hec ontrols ystem whichc onsistso fP LCa ndf requencyc onvertera ndi ts application in the buffer conveyor for cigarettes. The system constitute, hardware disposal and realization method are also presented in detail.Keywords:PLC f requencyc onverter b ufferc onveyor
上传时间： 2013-10-22
上传用户：ouyang426
最新的支持向量机工具箱，有了它会很方便 1. Find time to write a proper list of things to do! 2. Documentation. 3. Support Vector Regression. 4. Automated model selection. REFERENCES ========== [1] V.N. Vapnik, "The Nature of Statistical Learning Theory", Springer-Verlag, New York, ISBN 0-387-94559-8, 1995. [2] J. C. Platt, "Fast training of support vector machines using sequential minimal optimization", in Advances in Kernel Methods - Support Vector Learning, (Eds) B. Scholkopf, C. Burges, and A. J. Smola, MIT Press, Cambridge, Massachusetts, chapter 12, pp 185-208, 1999. [3] T. Joachims, "Estimating the Generalization Performance of a SVM Efficiently", LS-8 Report 25, Universitat Dortmund, Fachbereich Informatik, 1999.
上传时间： 2013-12-16
上传用户：亚亚娟娟123
USB Manager(usbmgr) 0.4.8 Shuu Yamaguchi <shuu@wondernetworkresources.com> Special Helper: Philipp Thomas When USB devices connect to or disconnect from a USB hub, the usbmgr works as the following according to configuration. a) It loads and unloads files Linux kernel modules. b) It execute file to setup USB devices.
标签： wondernetworkresources Yamaguchi Manager Special
上传时间： 2014-01-27
上传用户：zhaiyanzhong
mp3设计程序资料，采用c语言编写。 README file for yampp-3 source code 2001-05-27 This is the current state of the yampp-3 source code, 2001-05-27. This code is intended to run on Rev. B of the yampp-3 PCB, but can ofcourse be used on compatible systems as well. It still uses the "old" song selection system as the yampp-2. However, the disk handling routines has improved a lot and the obviosly, the new VS1001 handling has been put in. The codesize is almost at it s maximum at 1F40 bytes. A .ROM file is included if you don t have the compiler set up. For now, the documentation is in the code
上传时间： 2015-04-13
上传用户：小码农lz
prolog 找路例子程序： === === === === === === Part 1-Adding connections Part 2-Simple Path example | ?- path1(a,b,P,T). will produce the response: T = 15 P = [a,b] ? Part 3 - Non-repeating path As an example, the query: ?- path2(a,h,P,T). will succeed and may produce the bindings: P = [a,depot,b,d,e,f,h] T = 155 Part 4 - Generating a path below a cost threshold As an example, the query: ?- path_below_cost(a,[a,b,c,d,e,f,g,h],RS,300). returns: RS = [a,b,depot,c,d,e,g,f,h] ? RS = [a,c,depot,b,d,e,g,f,h] ? no ==================================
标签： Part connections example prolog
上传时间： 2015-04-24
上传用户：ljt101007
数字运算，判断一个数是否接近素数 A Niven number is a number such that the sum of its digits divides itself. For example, 111 is a Niven number because the sum of its digits is 3, which divides 111. We can also specify a number in another base b, and a number in base b is a Niven number if the sum of its digits divides its value. Given b (2 <= b <= 10) and a number in base b, determine whether it is a Niven number or not. Input Each line of input contains the base b, followed by a string of digits representing a positive integer in that base. There are no leading zeroes. The input is terminated by a line consisting of 0 alone. Output For each case, print "yes" on a line if the given number is a Niven number, and "no" otherwise. Sample Input 10 111 2 110 10 123 6 1000 8 2314 0 Sample Output yes yes no yes no
上传时间： 2015-05-21
上传用户：daguda
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])
标签： experience elliptical decompose important
上传时间： 2015-06-23
上传用户：372825274
光学设计软件zemax源码： This DLL models an nular aspheric surface as described in: "Annular surfaces in annular field systems" By Jose M. Sasian Opt. eng. 36 (12) P 3401-3401 December 1997 This surface is essentially an odd aspheric surface with an offset in the aspheric terms. The sag is given by: Z = (c*r*r) / (1+(1-((1+k)*c*c*r*r))^ 1/2 ) + a*(r-q)^2 + b*(r-q)^3 + c*(r-q)^4 + ... Note the terms a, b, c, ... have units of length to the -1, -2, -3, ... power.
标签： described aspheric surfaces Annular
上传时间： 2014-01-08
上传用户：yyyyyyyyyy
