The use of optical free-space emissions to provide indoor wireless commu- nications has been studied extensively since the pioneering work of Gfeller and Bapst in 1979 [1]. These studies have been invariably interdisciplinary in- volving such far flung areas such as optics design? indoor propagation studies? electronics design? communications systems design among others. The focus of this text is on the design of communications systems for indoor wireless optical channels. Signalling techniques developed for wired fibre optic net- works are seldom efficient since they do not consider the bandwidth restricted nature of the wireless optical channel.
標(biāo)簽： Communication Wireless optical Systems
上傳時(shí)間： 2020-06-01
上傳用戶：shancjb
ANSI-VITA 66.0-2016 optical Interconnect on VPX – Base Standard
標(biāo)簽： ANSI-VITA
上傳時(shí)間： 2022-06-26
上傳用戶：
近年來(lái)提出的光突發(fā)交換OBS(optical．Burst Switching)技術(shù)，結(jié)合了光路交換(OCS)與光分組交換(OPS)的優(yōu)點(diǎn)，有效支持高突發(fā)、高速率的多種業(yè)務(wù)，成為目前研究的熱點(diǎn)和前沿。 本論文圍繞國(guó)家“863”計(jì)劃資助課題“光突發(fā)交換關(guān)鍵技術(shù)和試驗(yàn)系統(tǒng)”，主要涉及兩個(gè)方面：LOBS邊緣節(jié)點(diǎn)核心板和光板FPGA的實(shí)現(xiàn)方案，重點(diǎn)關(guān)注于邊緣節(jié)點(diǎn)核心板突發(fā)包組裝算法。 本文第一章首先介紹LOBS網(wǎng)絡(luò)的背景、架構(gòu)，分析了LOBS網(wǎng)絡(luò)的關(guān)鍵技術(shù)，然后介紹了本論文后續(xù)章節(jié)研究的主要內(nèi)容。 第二章介紹了LOBS邊緣節(jié)點(diǎn)的總體結(jié)構(gòu)，主要由核心板和光板組成。核心板包括千兆以太網(wǎng)物理層接入芯片，突發(fā)包組裝FPGA，突發(fā)包調(diào)度FPGA，SDRAM以及背板驅(qū)動(dòng)芯片($2064)等硬件模塊。光板包括$2064，發(fā)射FPGA，接收FPGA，光發(fā)射機(jī)，光接收機(jī)，CDR等硬件模塊。論文對(duì)這些軟硬件資源進(jìn)行了詳細(xì)介紹，重點(diǎn)關(guān)注于各FPGA與其余硬件資源的接口。 第三章闡明了LOBS邊緣節(jié)點(diǎn)FPGA的具體實(shí)現(xiàn)方法，分為核心板突發(fā)包組裝FPGA和光板FPGA兩部分。核心板FPGA對(duì)數(shù)據(jù)和描述信息分別存儲(chǔ)，僅對(duì)描述信息進(jìn)行處理，提高了組裝效率。在維護(hù)突發(fā)包信息時(shí)，實(shí)時(shí)查詢和更新FEC配置表，保證了對(duì)FEE狀態(tài)表維護(hù)的靈活性。在讀寫(xiě)SDRAM時(shí)都采用整頁(yè)突發(fā)讀寫(xiě)模式，對(duì)MAC幀整幀一次性寫(xiě)入，讀取時(shí)采用超前預(yù)讀模式，對(duì)SDRAM內(nèi)存的使用采取即時(shí)申請(qǐng)方式，十分靈活高效。光板FPGA分為發(fā)射和接收兩個(gè)方向，主要是將進(jìn)入FPGA的數(shù)據(jù)進(jìn)行同步后按照指定的格式發(fā)送。 第四章總結(jié)了論文的主要內(nèi)容，并對(duì)LOBS技術(shù)進(jìn)行展望。本論文組幀算法采用動(dòng)態(tài)組裝參數(shù)表的方法，可以充分支持各種擴(kuò)展，包括自適應(yīng)動(dòng)態(tài)組裝算法。
標(biāo)簽： LOBS FPGA 節(jié)點(diǎn)
上傳時(shí)間： 2013-05-26
上傳用戶：AbuGe
隨著集成電路頻率的提高和多核時(shí)代的到來(lái)，傳統(tǒng)的高速電互連技術(shù)面臨著越來(lái)越嚴(yán)重的瓶頸問(wèn)題，而高速下的光互連具有電互連無(wú)法比擬的優(yōu)勢(shì)，成為未來(lái)電互連的理想替代者，也成為科學(xué)研究的熱點(diǎn)問(wèn)題。目前，由OIF(optical Intemetworking Forum，光網(wǎng)絡(luò)論壇)論壇提出的甚短距離光互連協(xié)議，主要面向主干網(wǎng)，其延遲、功耗、兼容性等都不能滿足板間、芯片間光互連的需要，因此，研究定制一種適用于板級(jí)、芯片級(jí)的光互連協(xié)議具有非常重要的研究意義。 本論文將協(xié)議功能分為數(shù)據(jù)鏈路層和物理層來(lái)設(shè)計(jì)，鏈路層功能包括了協(xié)議原語(yǔ)設(shè)計(jì)，數(shù)據(jù)幀格式和數(shù)據(jù)傳輸流程設(shè)計(jì)，流量控制機(jī)制設(shè)計(jì)，協(xié)議通道初始化設(shè)計(jì)，錯(cuò)誤檢測(cè)機(jī)制設(shè)計(jì)和空閑字符產(chǎn)生、時(shí)鐘補(bǔ)償方式設(shè)計(jì)；物理層功能包含了數(shù)據(jù)的串化和解串功能，多通道情況下的綁定功能，數(shù)據(jù)編解碼功能等。 然后，文章采用FPGA(Field Programmable Gate Array,現(xiàn)場(chǎng)可編程門(mén)陣列)技術(shù)實(shí)現(xiàn)了定制協(xié)議的單通道模式。重點(diǎn)是數(shù)據(jù)鏈路層的實(shí)現(xiàn)，物理層采用定制具備其功能的IP(Intellectual Property,知識(shí)產(chǎn)權(quán))——RocketIO來(lái)實(shí)現(xiàn)。實(shí)現(xiàn)的過(guò)程中，采用了Xilinx公司的ISE(Integrated System Environment,集成開(kāi)發(fā)環(huán)境)開(kāi)發(fā)流程，使用的設(shè)計(jì)工具包括:ISE，ModelSim，Synplify Pro,ChipScope等。 最后，本文對(duì)實(shí)現(xiàn)的協(xié)議進(jìn)行了軟件仿真和上扳測(cè)試，訪真和測(cè)試結(jié)果表明，實(shí)現(xiàn)的單通道模式，支持的最高串行頻率達(dá)到3.5GHz，完全滿足了光互連驗(yàn)證系統(tǒng)初期的要求，同時(shí)由RocketIO的高速串行差分口得到的眼圖質(zhì)量良好，表明對(duì)物理層IP的定制是成功的。
標(biāo)簽： FPGA 板級(jí) 光互連 協(xié)議研究
上傳時(shí)間： 2013-06-28
上傳用戶：guh000
Abstract: The DS4830 optical microcontroller's analog-to-digital converter (ADC) offset can change with temperature and gainselection. However, the DS4830 allows users to measure the ADC internal offset. The measured ADC offset is added to the ADCoffset register to nullify the offset error. This application note demonstrates the DS4830's ADC internal offset calibration in theapplication program.
標(biāo)簽： 4830 ADC DS 校準(zhǔn)
上傳時(shí)間： 2014-12-23
上傳用戶：萍水相逢
OPTOELECTRONICS CIRCUIT COLLECTION AVALANCHE PHOTODIODE BIAS SUPPLY 1Provides an output voltage of 0V to +80V for reverse biasingan avalanche photodiode to control its gain. This circuit canalso be reconfigured to supply a 0V to –80V output.LINEAR TEC DRIVER–1This is a bridge-tied load (BTL) linear amplifier for drivinga thermoelectric cooler (TEC). It operates on a single +5Vsupply and can drive ±2A into a common TEC.LINEAR TEC DRIVER–2This is very similar to DRIVER–1 but its power output stagewas modified to operate from a single +3.3V supply in orderto increase its efficiency. Driving this amplifier from astandard +2.5V referenced signal causes the output transistorsto have unequal power dissipation.LINEAR TEC DRIVER–3This BTL TEC driver power output stage achieves very highefficiency by swinging very close to its supply rails, ±2.5V.This driver can also drive ±2A into a common TEC. Operationis shown with the power output stage operating on±1.5V supplies. Under these conditions, this linear amplifiercan achieve very high efficiency. Application ReportThe following collection of analog circuits may be useful in electro-optics applications such as optical networkingsystems. This page summarizes their salient characteristics.
標(biāo)簽： 光電轉(zhuǎn)換 電路設(shè)計(jì)
上傳時(shí)間： 2013-10-27
上傳用戶：落花無(wú)痕
Many complex systems—such as telecom equipment,memory modules, optical systems, networking equipment,servers and base stations—use FPGAs and otherdigital ICs that require multiple voltage rails that muststart up and shut down in a specific order, otherwise theICs can be damaged. The LTC®2924 is a simple andcompact solution to power supply sequencing in a 16-pinSSOP package (see Figures 1 and 2).
上傳時(shí)間： 2013-10-29
上傳用戶：tonyshao
Piezoelectric motors are used in digital cameras for autofocus,zooming and optical image stabilization. Theyare relatively small, lightweight and effi cient, but theyalso require a complicated driving scheme. Traditionally,this challenge has been met with the use ofseparatecircuits, including a step-up converter and an oversizedgeneric full-bridge drive IC. The resulting high componentcount and large board space are especially problematicin the design of cameras for ever shrinking cell phones.The LT®3572 solves these problems by combining astep-up regulator and a dual full-bridge driver in a 4mm× 4mm QFN package. Figure 1 shows a typical LT3572Piezo motor drive circuit. A step-up converter is usedto generate 30V from a low voltage power source suchas a Li-Ion battery or any input power source within thepart’s wide input voltage range of 2.7V to 10V. The highoutput voltage of the step-up converter, adjustable upto 40V, is available for the drivers at the VOUT pin. Thedrivers operate in a full-bridge fashion, where the OUTAand OUTB pins are the same polarity as the PWMA andPWMB pins, respectively, and the OUTA and OUTB pinsare inverted from PWMA and PWMB, respectively. Thestep-up converter and both Piezo drivers have their ownshutdown control. Figure 2 shows a typical layout
上傳時(shí)間： 2013-11-18
上傳用戶：hulee
Avalanche photodiodes (APDs) are widely utilized in laserbased fiberoptic systems to convert optical data intoelectrical form. The APD is usually packaged with a signalconditioning amplifier in a small module. An APD receivermodule and attendant circuitry appears in Figure 1. TheAPD module (figure right) contains the APD and a transimpedance(e.g., current-to-voltage) amplifier. An opticalport permits interfacing fiberoptic cable to the APD’sphotosensitive portion. The module’s compact constructionfacilitates a direct, low loss connection between theAPD and the amplifier, necessary because of the extremelyhigh speed data rates involved
標(biāo)簽： 雪崩 光電二極管 偏置電壓 電流檢測(cè)電路
上傳時(shí)間： 2013-10-25
上傳用戶：brain kung
A large group of fiber optic lasers are powered by DCcurrent. Laser drive is supplied by a current source withmodulation added further along the signal path. Thecurrent source, although conceptually simple, constitutesan extraordinarily tricky design problem. There are anumber of practical requirements for a fiber optic currentsource and failure to consider them can cause laser and/or optical component destruction.
上傳時(shí)間： 2013-10-30
上傳用戶：wanghui2438
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