VLAN(Virtual LAN),翻譯成中文是“虛擬局域網”。LAN 可以是由少數幾臺家用計算機構成的網絡,也可以是數以百計的計算機構成的企業網絡。VLAN 所指的LAN 特指使用路由器分割的網絡——也就是廣播域。廣播域,指的是廣播幀(目標MAC 地址全部為1)所能傳遞到的范圍,亦即能夠直接通信的范圍。在VLAN 未出現之前,一個二層交換機即是一個廣播域。
上傳時間: 2013-10-20
上傳用戶:FreeSky
VLAN(Virtual Local Area Network)的中文名為"虛擬局域網"。VLAN是一種將局域網設備從邏輯上劃分成一個個網段,從而實現虛擬工作組的新興數據交換技術。這一新興技術主要應用于交換機和路由器中,但主流應用還是在交換機之中。
標簽: VLAN
上傳時間: 2013-11-19
上傳用戶:comua
為提升虛擬儀器傳輸速率與實時性能,擴展監測范圍,在VC的軟件平臺上設計了一種全功能虛擬示波器。與傳統虛擬示波器相比,該系統采用嵌入式系統完成信號采集,采用工業以太網為傳輸介質,通過線性插值算法和多線程編程思想,實現波形顯示、參數計算、頻譜分析以及波形存儲及回放功能。實驗結果表明,該虛擬示波器可以實現20 kHz采樣頻率下的波形精確顯示,達到預期的各項指標。 Abstract: o enhance the transfer rate and real-time of virtual instrument performance, expand scope of monitoring, this paper uses the VCs software platform to design a fully functional virtual oscilloscope. Compared with traditional virtual oscilloscope, this system adopts the embedded system to complete the data acquisition, industrial Ethernet as the transmission medium used by the linear interpolation algorithm and multi-threaded programming ideas, namely to achieve waveform display, parameter calculation, spectrum analysis and waveform storage and playback. Experimental results show that the virtual oscilloscope can accurately display the waveform with 20kHz sampling frequency, and achieve the desired targets.
上傳時間: 2013-11-25
上傳用戶:wbwyl
The #1 Step-by-Step Guide to labviewNow Completely Updated for labview 8! Master labview 8 with the industry's friendliest, most intuitive tutorial: labview for Everyone, Third Edition. Top labview experts Jeffrey Travis and Jim Kring teach labview the easy way: through carefully explained, step-by-step examples that give you reusable code for your own projects! This brand-new Third Edition has been fully revamped and expanded to reflect new features and techniques introduced in labview 8. You'll find two new chapters, plus dozens of new topics, including Project Explorer, AutoTool, XML, event-driven programming, error handling, regular expressions, polymorphic VIs, timed structures, advanced reporting, and much more. Certified labview Developer (CLD) candidates will find callouts linking to key objectives on NI's newest exam, making this book a more valuable study tool than ever. Not just what to d why to do it! Use labview to build your own virtual workbench Master labview's foundations: wiring, creating, editing, and debugging VIs; using controls and indicators; working with data structures; and much more Learn the "art" and best practices of effective labview development NEW: Streamline development with labview Express VIs NEW: Acquire data with NI-DAQmx and the labview DAQmx VIs NEW: Discover design patterns for error handling, control structures, state machines, queued messaging, and more NEW: Create sophisticated user interfaces with tree and tab controls, drag and drop, subpanels, and more Whatever your application, whatever your role, whether you've used labview or not, labview for Everyone, Third Edition is the fastest, easiest way to get the results you're after!
上傳時間: 2013-10-14
上傳用戶:shawvi
一篇長90頁的PPT和10個左右的示例源程序,對于自學能力強且有一定計算機編程基礎的人來說上手還是很快的。 •Understand the components of a Virtual Instrument •Introduce labview and common labview functions •Build a simple data acquisition application •Create a subroutine in labview
上傳時間: 2013-11-21
上傳用戶:yeling1919
虛擬儀器(virtual instrumention)是基于計算機的儀器。計算機和儀器的密切結合是目前儀器發展的一個重要方向。粗略地說這種結合有兩種方式,一種是將計算機裝入儀器,其典型的例子就是所謂智能化的儀器。隨著計算機功能的日益強大以及其體積的日趨縮小,這類儀器功能也越來越強大,目前已經出現含嵌入式系統的儀器。另一種方式是將儀器裝入計算機。以通用的計算機硬件及操作系統為依托,實現各種儀器功能。虛擬儀器主要是指這種方式。下面的框圖反映了常見的虛擬儀器方案。 虛擬儀器的主要特點有: n 盡可能采用了通用的硬件,各種儀器的差異主要是軟件。 n 可充分發揮計算機的能力,有強大的數據處理功能,可以創造出功能更強的儀器。 n 用戶可以根據自己的需要定義和制造各種儀器。 虛擬儀器實際上是一個按照儀器需求組織的數據采集系統。虛擬儀器的研究中涉及的基礎理論主要有計算機數據采集和數字信號處理。目前在這一領域內,使用較為廣泛的計算機語言是美國NI公司的labview。 虛擬儀器的起源可以追朔到20世紀70年代,那時計算機測控系統在國防、航天等領域已經有了相當的發展。PC機出現以后,儀器級的計算機化成為可能,甚至在Microsoft公司的Windows誕生之前,NI公司已經在Macintosh計算機上推出了labview2.0以前的版本。對虛擬儀器和labview長期、系統、有效的研究開發使得該公司成為業界公認的權威。 普通的PC有一些不可避免的弱點。用它構建的虛擬儀器或計算機測試系統性能不可能太高。目前作為計算機化儀器的一個重要發展方向是制定了VXI標準,這是一種插卡式的儀器。每一種儀器是一個插卡,為了保證儀器的性能,又采用了較多的硬件,但這些卡式儀器本身都沒有面板,其面板仍然用虛擬的方式在計算機屏幕上出現。這些卡插入標準的VXI機箱,再與計算機相連,就組成了一個測試系統。VXI儀器價格昂貴,目前又推出了一種較為便宜的PXI標準儀器。 虛擬儀器研究的另一個問題是各種標準儀器的互連及與計算機的連接。目前使用較多的是IEEE 488或GPIB協議。未來的儀器也應當是網絡化的。
上傳時間: 2013-10-15
上傳用戶:gaoliangncepu
Abstract: This article describes the Antenna Interface Standards Group (AISG) standard in telecommunications and details itshardware implementation. It explains how a fully integrated transceiver such as the MAX9947 can help reduce space and cost, andsolve bus arbitrations in base-station tower equipment.
上傳時間: 2014-12-30
上傳用戶:wangchong
虛擬串口軟件
標簽: Virtual Serial Driver Port
上傳時間: 2013-10-27
上傳用戶:1234321@q
虛擬串口軟件
標簽: Virtual Serial Driver Port
上傳時間: 2013-10-23
上傳用戶:JIUSHICHEN
Most designers wish to utilize as much of a device as possible in order to enhance the overallproduct performance, or extend a feature set. As a design grows, inevitably it will exceed thearchitectural limitations of the device. Exactly why a design does not fit can sometimes bedifficult to determine. Programmable logic devices can be configured in almost an infinitenumber of ways. The same design may fit when you use certain implementation switches, andfail to fit when using other switches. This application note attempts to clarify the CPLD softwareimplementation (CPLDFit) options, as well as discuss implementation tips in CoolRunnerTM-IIdesigns in order to maximize CPLD utilization.
上傳時間: 2014-01-11
上傳用戶:a471778