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A Computer-On-Module, or COM, is a Module with all components necessary for a bootable host computer, packaged as a super component. A COM requires a Carrier Board to bring out I/O and to power up. COMs are used to build single board computer solutions and offer OEMs fast time-to-market with reduced development cost. Like integrated circuits, they provide OEMs with significant freedom in meeting form-fit-function requirements. For all these reasons the COM methodology has gained much popularity with OEMs in the embedded industry. COM Express® is an open industry standard for Computer-On-Modules. It is designed to be future proof and to provide a smooth transition path from legacy parallel interfaces to LVDS (Low Voltage Differential Signaling) interfaces. These include the PCI bus and parallel ATA on the one hand and PCI Express and Serial ATA on the other hand.
標(biāo)簽：
PICMG_COM
COMe
上傳時(shí)間：
2013-11-05
上傳用戶：Wwill
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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frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element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.
標(biāo)簽：
差分電路
單端
模式
上傳時(shí)間：
2014-03-25
上傳用戶：yyyyyyyyyy
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為了在CDMA系統(tǒng)中更好地應(yīng)用QDPSK數(shù)字調(diào)制方式，在分析四相相對移相（QDPSK)信號(hào)調(diào)制解調(diào)原理的基礎(chǔ)上，設(shè)計(jì)了一種QDPSK調(diào)制解調(diào)電路，它包括串并轉(zhuǎn)換、差分編碼、四相載波產(chǎn)生和選相、相干解調(diào)、差分譯碼和并串轉(zhuǎn)換電路。在MAX+PLUSⅡ軟件平臺(tái)上，進(jìn)行了編譯和波形仿真。綜合后下載到復(fù)雜可編程邏輯器件EPM7128SLC84-15中，測試結(jié)果表明，調(diào)制電路能正確選相，解調(diào)電路輸出數(shù)據(jù)與QDPSK調(diào)制輸入數(shù)據(jù)完全一致，達(dá)到了預(yù)期的設(shè)計(jì)要求。
Abstract:
In order to realize the better application of digital modulation mode QDPSK in the CDMA system， a sort of QDPSK modulation-demodulation circuit was designed based on the analysis of QDPSK signal modulation-demodulation principles. It included serial/parallel conversion circuit, Differential encoding circuit, four-phase carrier wave produced and phase chosen circuit, coherent demodulation circuit, difference decoding circuit and parallel/serial conversion circuit. And it was compiled and simulated on the MAX+PLUSⅡ software platform,and downloaded into the CPLD of EPM7128SLC84-15.The test result shows that the modulation circuit can exactly choose the phase，and the output data of the demodulator circuit is the same as the input data of the QDPSK modulate. The circuit achieves the prospective requirement of the design.
標(biāo)簽：
QDPSK
CPLD
調(diào)制解調(diào)
電路設(shè)計(jì)
上傳時(shí)間：
2013-10-28
上傳用戶：jyycc
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Calculation of the Differential Impedance of Tracks on FR4 substrates
There is a discrepancy between calculated and measured values of impedance for Differential transmission lineson FR4. This is especially noticeable in the case of surface microstrip configurations. The anomaly is shown tobe due to the nature of the substrate material. This needs to be considered as a layered structure of epoxy resinand glass fibre. Calculations, using Boundary Element field methods, show that the distribution of the electricfield within this layered structure determines the apparent dielectric constant and therefore affects theimpedance. Thus FR4 cannot be considered to be uniform dielectric when calculating Differential impedance.
標(biāo)簽：
FR4
計(jì)算
差分阻抗
上傳時(shí)間：
2013-10-18
上傳用戶：masochism
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用JAVA語言編寫，包括PSO（Particle swarm optimization, 中文譯名為粒子群優(yōu)化或微粒群算法), DE (Differential evolution, 中文譯名為差分進(jìn)化或差異演化)等算法，有一些不帶約束和帶約束的算例（如Michelawicz的幾個(gè)問題）。使用說明見usage.txt、RUNExample.bat和程序中的注釋。
標(biāo)簽：
JAVA
語言
編寫
上傳時(shí)間：
2014-01-06
上傳用戶：agent
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The purpose of this application note is to describe the main elements of
an RS-422 and RS-485 system. This application note attempts to cover
enough technical details so that the system designer will have considered all
the important aspects in his data system design. Since both RS-422 and RS-
485 are data transmission systems that use balanced Differential signals, it is
appropriate to discuss both systems in the same application note. Throughout
this application note the generic terms of RS-422 and RS-485 will be used to
represent the EIA/TIA-422 and EIA/TIA-485 Standards.
標(biāo)簽：
application
describe
elements
purpose
上傳時(shí)間：
2013-12-29
上傳用戶：sxdtlqqjl
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CLAWPACK is a software package designed to compute numerical solutions to hyperbolic partial Differential equations using a wave propagation approach
標(biāo)簽：
hyperbolic
numerical
solutions
CLAWPACK
上傳時(shí)間：
2014-01-03
上傳用戶：woshini123456
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matlab 求解微分方程 ，This module Does FEM analysis of a field problem when the Governing Differential equation
標(biāo)簽：
matlab
微分方程
上傳時(shí)間：
2016-06-02
上傳用戶：二驅(qū)蚊器
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數(shù)值分析算法源碼(java)
這個(gè)學(xué)期一邊學(xué)習(xí)java一邊學(xué)習(xí)數(shù)值分析,因此用java寫了一個(gè)數(shù)值分析算法的軟件包numericalAnalysis.
[說明]
適合使用者:會(huì)java的,想要學(xué)習(xí)數(shù)值分析算法的人.
本代碼對照書:數(shù)值分析第二版,史萬明等編,北京理工大學(xué)出版社.
本代碼盡量按書中描述的來寫,可以提供參考.
[使用方法]
在java的ide中新建一個(gè)項(xiàng)目,把numericalAnalysis包直接拷貝到此項(xiàng)目的源文件夾中,然后要解決什么問題,就相應(yīng)的編譯運(yùn)行什么包.
另外有這些類的API提供參考,可以自己根據(jù)自己要求寫驅(qū)動(dòng)類.運(yùn)行API文件夾中的index.html文件就行.
[包的結(jié)構(gòu)]
numericalAnalysis包中又含有9個(gè)包,除function包的是接口外,其余包都含有一個(gè)獨(dú)立的數(shù)值分析問題的類以及其驅(qū)動(dòng)類.9個(gè)包如下:
Differential:微分問題
equation:方程
function:只含一個(gè)接口,用來讓用戶寫自己的函數(shù)
functionApproximation:離散情況下函數(shù)逼近問題
integration:積分問題
interpolation:插值問題
linearEquationGroup:線性方程組問題(包括過定方程組)
norm:求解向量和矩陣的范數(shù)
ode:常微分方程數(shù)值解的求解
標(biāo)簽：
java
numericalAnalysis
數(shù)值分析
算法
上傳時(shí)間：
2014-01-04
上傳用戶：wff
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Toolbox for Numerical Computing with MATLAB （by Cleve Moler).
Numerical Computing with MATLAB （by Cleve Moler) is a textbook for an introductory course
in numerical methods, Matlab, and technical computing. The emphasis is on in-
formed use of mathematical software. We want you learn enough about the mathe-
matical functions in Matlab that you will be able to use them correctly, appreciate
their limitations, and modify them when necessary to suit your own needs. The
topics include
* introduction to Matlab,
* linear equations,
* interpolation,
* zero and roots,
* least squares,
* quadrature,
* ordinary di?erential equations,
* random numbers,
* Fourier analysis,
* eigenvalues and singular values,
* partial Differential equations.
標(biāo)簽：
Numerical
Computing
MATLAB
with
上傳時(shí)間：
2014-01-01
上傳用戶：guanliya
