磁芯電感器的諧波失真分析 摘 要：簡(jiǎn)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(duì)諧波測(cè)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(jiǎn)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(duì)罐形磁心詳細(xì)的測(cè)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(cè)量磁心產(chǎn)生的非線性失真。這種相對(duì)比較的實(shí)用方法，專用于無中心柱配對(duì)罐形磁心的諧波衰耗測(cè)試。 這種磁心主要用于載波電報(bào)、電話設(shè)備的遙測(cè)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(cè)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(cè)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(cè)磁心配對(duì)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(cè)得的主波電平 （P2）為+17.4 dB，然后在33′端子處測(cè)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(cè)量是一項(xiàng)很精細(xì)的工作，其中測(cè)量系統(tǒng)的高、低通濾波器，信號(hào)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(duì)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(guó)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： 2014-12-24
上傳用戶：7891
Abstract: Rail splitting is creating an artificial virtual ground as a reference voltage. It is used to set the signalto match the op amp's "sweet spot." An op amp has the most linear- and distortion-free qualities at that sweetspot. Typically, the sweet spot occurs near the center between the single power rail and ground. In the case ofa number of signals, the virtual ground can control channel DC errors when multiplexing or switching thesignals.
標(biāo)簽： 電源調(diào)整 虛擬地
上傳時(shí)間： 2013-10-23
上傳用戶：wushengwu
隨著Android平臺(tái)在移動(dòng)終端的市場(chǎng)占有率越來越高，安卓應(yīng)用的開發(fā)周期越來越短，繁冗且效率底下的Java在新的形勢(shì)下已漸漸表現(xiàn)出它的疲態(tài)，為了解決Android應(yīng)用開發(fā)語言單一的問題，Google發(fā)起了SL4A（The Scripting Layer for Android）項(xiàng)目。本文簡(jiǎn)單的介紹了SL4A的工作原理，并以Eclipse和Android SDK為開發(fā)工具，在SL4A的支持下使用Python語言實(shí)現(xiàn)Android應(yīng)用GUI的開發(fā)。
上傳時(shí)間： 2013-11-01
上傳用戶：s363994250
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(jì)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(dòng)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(jià)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(shí)間： 2013-11-14
上傳用戶：ynwbosss
在深入了解Flash存儲(chǔ)器的基礎(chǔ)上，采用單片機(jī)自動(dòng)檢測(cè)存儲(chǔ)器無效塊。主要通過讀取每一塊的第1、第2頁內(nèi)容，判斷該塊的好壞，并給出具體的實(shí)現(xiàn)過程，以及部分關(guān)鍵的電路原理圖和C語言程序代碼。該設(shè)計(jì)最終實(shí)現(xiàn)單片機(jī)自動(dòng)檢測(cè)Flash壞塊的功能，并通過讀取ID號(hào)檢測(cè)Flash的性能，同時(shí)該設(shè)計(jì)能夠存儲(chǔ)和讀取1GB數(shù)據(jù)。 Abstract: On the basis of in-depth understanding the Flash chips，this paper designs a new program which using the SCM to detect the invalid block.Mainly through reading the data of the first and second page to detect the invalid block.Specific implementation procedure was given,and the key circuit schematic diagram and C language program code was introduced.This design achieved the function of using the MCU checks the invalid block finally，and increased the function by reading the ID number of Flash to get the performance of the memory.And the design also can write and read1GB data
標(biāo)簽： Flash 單片機(jī) 存儲(chǔ)器 自動(dòng)檢測(cè)
上傳時(shí)間： 2013-10-25
上傳用戶：taozhihua1314
該系統(tǒng)由單片機(jī)89S52控制模塊，程控寬帶放大模塊，整形模塊，F(xiàn)PGA內(nèi)頻率、相位差測(cè)量模塊等構(gòu)成，采用等精度測(cè)頻法測(cè)出頻率和周期，可測(cè)量有效值為0.01～5V，頻率范圍1Hz～20MHz信號(hào)的頻率、周期信號(hào)，精度高達(dá)10-6。采用計(jì)數(shù)法測(cè)量相位差，該系統(tǒng)可測(cè)量有效值0.5～5V，頻率10Hz～100kHz信號(hào)的相位差，精度為1°。系統(tǒng)功能由按鍵控制，測(cè)量結(jié)果實(shí)時(shí)顯示，人機(jī)界面友好。 Abstract: The system consists of the following functional blocks:89S52microcontroller controlling module,programmable amplifier module,comparator module,frequency and phase difference testing module in the FPGA.The system use the equal accuracy frequency-examining technique it measures frequency and circle of signal which its ranges is from1Hz to20MHz and the amplitude of which its range is from0.01Vrms to5Vrms,precision is up to10-6.Using of count method,the system detects the phase difference of signal,the amplitude of whic its range is from0.5Vrms to5Vrms and the frequency of which its ranges is from10Hz to100kHz,precision is up to1°,The system functions is controlled by certain keys,measurement results are displayed in real-time and it is friendly interface.
標(biāo)簽： 89S52 單片機(jī) 多功能 計(jì)數(shù)器
上傳時(shí)間： 2013-11-04
上傳用戶：CHINA526
從系統(tǒng)硬件設(shè)計(jì)和軟件構(gòu)成上，介紹一種以AT89C52單片機(jī)為核心,通過無線遙控方法實(shí)現(xiàn)對(duì)預(yù)設(shè)電話自動(dòng)撥號(hào)報(bào)警的智能呼救系統(tǒng)。系統(tǒng)提供了患者在緊急情況下無法使用電話報(bào)警時(shí)的一種報(bào)警手段。由用戶預(yù)設(shè)的多組電話號(hào)碼作為語音報(bào)警對(duì)象,預(yù)錄可長(zhǎng)達(dá)20 s的語音信號(hào)來說明患者所處地點(diǎn)及病情，并通知患者家人。 Abstract: This paper introduces a intelligent alarming system which is realized by wireless remote control system.This system chiefly consists of AT89C51 the system can processor.User can input several groups of telephone number regarded as alarming objects,The system can record some information 20 seconds to tell the site of the patient.And notice the rokonok of the patient.
上傳時(shí)間： 2013-11-19
上傳用戶：wd450412225
將現(xiàn)行的供暖計(jì)費(fèi)方式由按建筑面積計(jì)費(fèi)變?yōu)榘聪牡臒崮苡?jì)費(fèi)是供暖計(jì)費(fèi)方式發(fā)展趨勢(shì)，為了滿足這一計(jì)費(fèi)方式變化的需要，設(shè)計(jì)了基于IC卡的預(yù)付費(fèi)式新型供暖計(jì)費(fèi)系統(tǒng)，通過測(cè)量用戶采暖系統(tǒng)進(jìn)出口的溫度和流量，計(jì)算用戶消耗的熱能，利用IC卡記錄用戶預(yù)付費(fèi)的金額和當(dāng)年熱能的單價(jià)，根據(jù)熱能消耗和當(dāng)年熱能的單價(jià)計(jì)算用戶采暖費(fèi)，根據(jù)實(shí)際發(fā)生的供暖費(fèi)用和預(yù)付費(fèi)金額控制供暖的開停，這一計(jì)費(fèi)方式的變化使供暖計(jì)費(fèi)更趨合理。 Abstract: It is trend that the mode of heat charging is changed from billing by building area to by thermal energy. In order to meet the needs of heat charging mode changing， a new system of heat charging based on IC card is proposed. The user?蒺s energy consumption is calculated by measuring the user inlet and outlet temperature and flow，using the IC card to record the prepaid amount and the current price of heat. The user?蒺s heating costs is calculated according to energy consumption and current price， according to actual heating costs and prepaid amount，the system controls the heating opening or stopping. It is more reasonable that calculated heating costs by user heat consumption
標(biāo)簽： IC卡 計(jì)費(fèi) 系統(tǒng)設(shè)計(jì)
上傳時(shí)間： 2013-10-14
上傳用戶：大融融rr
Atmel AVR 單片機(jī)上網(wǎng)方案 The AVR Embedded Internet Toolkit is the fastest way to connect anyembedded design to the Internet. It includes an ATmega AVR microcontroller,dedicated hardware, and all required software protocols forconnecting to the Internet. The AVR Embedded Internet Toolkit is thefastest choice for getting started with embedded Internet and for developinga complete embedded application connected to the Internet.
標(biāo)簽： Atmel AVR 單片機(jī) 方案
上傳時(shí)間： 2013-11-06
上傳用戶：xjz632
The 87C576 includes two separate methods of programming theEPROM array, the traditional modified Quick-Pulse method, and anew On-Board Programming technique (OBP).Quick Pulse programming is a method using a number of devicepins in parallel (see Figure 1) and is the traditional way in which87C51 family members have been programmed. The Quick-Pulsemethod supports the following programming functions:– program USER EPROM– verify USER EPROM– program KEY EPROM– program security bits– verify security bits– read signature bytesThe Quick-Pulse method is quite easily suited to standardprogramming equipment as evidenced by the numerous vendors of87C51 compatible programmers on the market today. Onedisadvantage is that this method is not well suited to programming inthe embedded application because of the large number of signallines that must be isolated from the application. In addition, parallelsignals from a programmer would need to be cabled to theapplication’s circuit board, or the application circuit board wouldneed to have logic built-in to perform the programming functions.These requirements have generally made in-circuit programmingusing the modified Quick Pulse method impractical in almost all87C51 family applications.
上傳時(shí)間： 2013-10-21
上傳用戶：xiaozhiqban
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