Single-Ended and Differential S-Parameters Differential circuits have been important incommunication systems for many years. In the past,differential communication circuits operated at lowfrequencies, where they could be designed andanalyzed using lumped-element models andtechniques. With the frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element techniques.Scattering parameters, or S-parameters, have beendeveloped for this purpose [1]. These S-parametersare defined for single-ended networks. S-parameterscan be used to describe differential networks, but astrict definition was not developed until Bockelmanand others addressed this issue [2]. Bockelman’swork also included a study on how to adapt single-ended S-parameters for use with differential circuits[2]. This adaptation, called “mixed-mode S-parameters,” addresses differential and common-mode operation, as well as the conversion betweenthe two modes of operation.This application note will explain the use of single-ended and mixed-mode S-parameters, and the basicconcepts of microwave measurement calibration.
上傳時間： 2014-03-25
上傳用戶：yyyyyyyyyy
Multioutput monolithic regulators are easy to use and fi tinto spaces where multichip solutions cannot. Nevertheless,the popularity of multioutput regulators is temperedby a lack of options for input voltages above 30V andsupport of high output currents. The LT3692A fi lls thisgap with a dual monolithic regulator that operates frominputs up to 36V. It also includes a number of channeloptimization features that allow the LT3692A’s per-channelperformance to rival that of multichip solutions.
上傳時間： 2014-01-03
上傳用戶：Huge_Brother
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).
上傳時間： 2013-10-10
上傳用戶：geshaowei
The LPC1850/30/20/10 are ARM Cortex-M3 based microcontrollers for embeddedapplications. The ARM Cortex-M3 is a next generation core that offers systemenhancements such as low power consumption, enhanced debug features, and a highlevel of support block integration.The LPC1850/30/20/10 operate at CPU frequencies of up to 150 MHz. The ARMCortex-M3 CPU incorporates a 3-stage pipeline and uses a Harvard architecture withseparate local instruction and data buses as well as a third bus for peripherals. The ARMCortex-M3 CPU also includes an internal prefetch unit that supports speculativebranching.The LPC1850/30/20/10 include up to 200 kB of on-chip SRAM data memory, a quad SPIFlash Interface (SPIFI), a State Configuration Timer (SCT) subsystem, two High-speedUSB controllers, Ethernet, LCD, an external memory controller, and multiple digital andanalog peripherals.
上傳時間： 2014-12-31
上傳用戶：zhuoying119
The LPC4350/30/20/10 are ARM Cortex-M4 based microcontrollers for embeddedapplications. The ARM Cortex-M4 is a next generation core that offers systemenhancements such as low power consumption, enhanced debug features, and a highlevel of support block integration.The LPC4350/30/20/10 operate at CPU frequencies of up to 150 MHz. The ARMCortex-M4 CPU incorporates a 3-stage pipeline, uses a Harvard architecture withseparate local instruction and data buses as well as a third bus for peripherals, andincludes an internal prefetch unit that supports speculative branching. The ARMCortex-M4 supports single-cycle digital signal processing and SIMD instructions. Ahardware floating-point processor is integrated in the core.The LPC4350/30/20/10 include an ARM Cortex-M0 coprocessor, up to 264 kB of datamemory, advanced configurable peripherals such as the State Configurable Timer (SCT)and the Serial General Purpose I/O (SGPIO) interface, two High-speed USB controllers,Ethernet, LCD, an external memory controller, and multiple digital and analog peripherals
上傳時間： 2013-10-28
上傳用戶：15501536189
The NXP LPC315x combine an 180 MHz ARM926EJ-S CPU core, High-speed USB 2.0OTG, 192 KB SRAM, NAND flash controller, flexible external bus interface, an integratedaudio codec, Li-ion charger, Real-Time Clock (RTC), and a myriad of serial and parallelinterfaces in a single chip targeted at consumer, industrial, medical, and communicationmarkets. To optimize system power consumption, the LPC315x have multiple powerdomains and a very flexible Clock Generation Unit (CGU) that provides dynamic clockgating and scaling.The LPC315x is implemented as multi-chip module with two side-by-side dies, one fordigital fuctions and one for analog functions, which include a Power Supply Unit (PSU),audio codec, RTC, and Li-ion battery charger.
上傳時間： 2014-01-17
上傳用戶：Altman
IBIS 模型在做類似板級SI 仿真得到廣泛應用。在做仿真的初級階段，經常對于ibis 模型的描述有些疑問，只知道把模型拿來轉換為軟件所支持的格式或者直接使用，而對于IBIS 模型里面的數據描述什么都不算很明白，因此下面的一些描述是整理出來的一點對于ibis 的基本理解。在此引用很多presention來描述ibis 內容（有的照抄過來，阿彌陀佛，不要說抄襲，只不過習慣信手拈來說明一些問題），僅此向如muranyi 等ibis 先驅者致敬。本文難免有些錯誤或者考慮不周，隨時歡迎進行討論并對其進行修改！IBIS 模型的一些基本概念IBIS 這個詞是Input/Output buffer information specification 的縮寫。本文是基于IBIS ver3.2 所撰寫出來（www.eigroup.org/IBIS/可下載到各種版本spec）,ver4.2增加很多新特性，由于在目前設計中沒用到不予以討論。。。在業界經常會把spice 模型描述為transistor model 是因為它描述很多電路細節問題。而把ibis 模型描述為behavioral model 是因為它并不象spice 模型那樣描述電路的構成，IBIS 模型描述的只不過是電路的一種外在表現，象個黑匣子一樣，輸入什么然后就得到輸出結果，而不需要了解里面驅動或者接收的電路構成。因此有所謂的garbage in, garbage out，ibis 模型的仿真精度依賴于模型的準確度以及考慮的worse case，因此無論你的模型如何精確而考慮的worse case 不周全或者你考慮的worse case 如何周全而模型不精確，都是得不到較好的仿真精度。
上傳時間： 2013-10-16
上傳用戶：zhouli
ExpressPCB 是一款免費的PCB設計軟件，簡單實使?？梢援嬰p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).
標簽： ExpressPCB PCB 設計軟件
上傳時間： 2013-11-15
上傳用戶：lchjng
溫濕度傳感器 sht11 仿真程序 sbit out =P3^0; //加熱口 //sbit input =P1^1;//檢測口 //sbit speek =P2^0;//報警 sbit clo =P3^7;//時鐘 sbit ST =P3^5;//開始 sbit EOC =P3^6;//成功信號 sbit gwei =P3^4;//個位 sbit swei =P3^3;//十位 sbit bwei =P3^2;//百位 sbit qwei =P3^1;//千位 sbit speak =P0^0;//報警音 sbit bjled =P0^1;//報警燈 sbit zcled =P0^2;//正常LED int count; uchar xianzhi;//取轉換結果 uchar seth;//高時間 uchar setl;//低時間 uchar seth_mi;//高時間 uchar setl_mi;//低時間 bit hlbz;//高低標志 bit clbz; bit spbz; ///定時中斷程序/// void t0 (void) interrupt 1 using 0 { TH0=(65536-200)/256;//5ms*200=1000ms=1s TL0=(65536-200)%256; clo=!clo;//產生時鐘 if(count>5000) { if(hlbz) { if(seth_mi==0){seth_mi=seth;hlbz=0;out=0;} else seth_mi--; } if(!hlbz) { if(setl_mi==0){setl_mi=setl;hlbz=1;out=1;} else setl_mi--; } count=0; } else count++; } ///////////// ///////延時/////// delay(int i) { while(--i); } ///////顯示處理/////// xianshi() { int abcd=0; int i; for (i=0;i<5;i++) { abcd=xianzhi; gwei=1; swei=1; bwei=1; qwei=1; P1=dispcode[abcd/1000]; qwei=0; delay(70); qwei=1; abcd=abcd%1000; P1=dispcode[abcd/100]; bwei=0; delay(70); bwei=1; abcd=abcd%100; P1=dispcode[abcd/10]; swei=0; delay(70); swei=1; abcd=abcd%10; P1=dispcode[abcd]; gwei=0; delay(70); gwei=1; } } doing() { if(xianzhi>100) {bjled=0;speak=1;zcled=1;} else {bjled=1;speak=0;zcled=0;} } void main(void) { seth=60;//h60秒 setl=90;//l90秒 seth_mi=60;//h60秒 setl_mi=90;//l90秒 TMOD=0X01;//定時0 16位工作模式 TH0=(65536-200)/256; TL0=(65536-200)%256; TR0=1; //開始計時 ET0=1; //開定時0中斷 EA=1; //開全中斷 while(1) { ST=0; _nop_(); ST=1; _nop_(); ST=0; // EOC=0; xianshi(); while(!EOC) { xianshi(); } xianzhi=P2; xianshi(); doing(); } }
上傳時間： 2013-11-07
上傳用戶：我們的船長
超聲波傳感器適用于對大幅的平面進行靜止測距。普通的超聲波傳感器測距范圍大概是 2cm~450cm，分辨率3mm（淘寶賣家說的，筆者測試環境沒那么好，個人實測比較穩定的 距離10cm~2m 左右，超過此距離就經常有偶然不準確的情況發生了，當然不排除筆者技術 問題。） 測試對象是淘寶上面最便宜的SRF-04 超聲波傳感器，有四個腳：5v 電源腳（Vcc），觸發控制端（Trig），接收端（Echo），地端（GND） 附:SRF 系列超聲波傳感器參數比較 模塊工作原理： 采用IO 觸發測距，給至少10us 的高電平信號； 模塊自動發送8個40KHz 的方波，自動檢測是否有信號返回； 有信號返回，通過IO 輸出一高電平，高電平持續的時間就是超聲波從發射到返回的時間．測試距離=(高電平時間*聲速(340m/s))/2; 電路連接方法 Arduino 程序例子： constintTrigPin = 2; constintEchoPin = 3; floatcm; voidsetup() { Serial.begin(9600); pinMode(TrigPin, OUTPUT); pinMode(EchoPin, INPUT); } voidloop() { digitalWrite(TrigPin, LOW); //低高低電平發一個短時間脈沖去TrigPin delayMicroseconds(2); digitalWrite(TrigPin, HIGH); delayMicroseconds(10); digitalWrite(TrigPin, LOW); cm = pulseIn(EchoPin, HIGH) / 58.0; //將回波時間換算成cm cm = (int(cm * 100.0)) / 100.0; //保留兩位小數 Serial.print(cm); Serial.print("cm"); Serial.println(); delay(1000); }
上傳時間： 2013-10-18
上傳用戶：星仔
