Optisen liityntäverkon ohjelmoitavien logiikkapiirien ohjelmoinnin suunnittelu

Tiedonsiirtoverkkojen rakenne elää muutoksen aikaa. Perinteisesti data-, puhelin- ja laajakaistaliikenne on siirretty erillisissä verkoissa, joiden samanaikainen ylläpitäminen tuottaa ylimääräisiä kustannuksia operaattoreille. Lisäksi uudet interaktiiviset palvelut vaativat toimiakseen sellaista palvelunlaatua, jota nykyiset tiedonsiirtoverkot eivät kykene tarjoamaan. Näiden epäkohtien johdosta tiedonsiirtoverkkojen kehityksessä tähdätään uusiin, entistä joustavampiin ja eri toiminnot yhdistäviin verkkoratkaisuihin, joissa tiedonsiirron palvelunlaadulla on entistä suurempi merkitys. Tällä hetkellä tiedonsiirtoverkkojen kokonaistiedonsiirtonopeuden kasvun pullonkaulatekijäksi on muodostunut kaupunkialueiden syöttöverkkojen monimutkaisuus, millä on suuri vaikutus myös tiedonsiirron palvelunlaatuun. TEKES-rahoitteisessa OAN-projektissa kehitetään uutta ja yksinkertaisempaa kaupunkialueen optista syöttöverkkoratkaisua, jolla alueen palvelunlaatua saataisiin parannettua. Tämä diplomityö on tehty osana OAN-projektia. Työssä kuvataan tiedonsiirtoverkkojen tämänhetkinen rakenne, tarkastellaan sen ongelmia ja tulevaisuuden kehityssuuntia, sekä esitetään pohdintojen pohjalta rakennettu malli tulevaisuuden tiedonsiirtoverkkojen rakenteelle. Työssä esitetään myös HDL-implementointiprosessiin kuuluvat työvaiheet sekä käydään läpi suunnitelma OAN-projektissa toteutettavan prototyypin ohjelmoitavien logiikkapiirien ohjelmaa varten

Design of energy efficient high speed I/O interfaces

Energy efficiency has become a key performance metric for wireline high speed I/O interfaces. Consequently, design of low power I/O interfaces has garnered large interest that has mostly been focused on active power reduction techniques at peak data rate. In practice, most systems exhibit a wide range of data transfer patterns. As a result, low energy per bit operation at peak data rate does not necessarily translate to overall low energy operation. Therefore, I/O interfaces that can scale their power consumption with data rate requirement are desirable. Rapid on-off I/O interfaces have a potential to scale power with data rate requirements without severely affecting either latency or the throughput of the I/O interface. In this work, we explore circuit techniques for designing rapid on-off high speed wireline I/O interfaces and digital fractional-N PLLs. A burst-mode transmitter suitable for rapid on-off I/O interfaces is presented that achieves 6 ns turn-on time by utilizing a fast frequency settling ring oscillator in digital multiplying delay-locked loop and a rapid on-off biasing scheme for current mode output driver. Fabricated in 90 nm CMOS process, the prototype achieves 2.29 mW/Gb/s energy efficiency at peak data rate of 8 Gb/s. A 125X (8 Gb/s to 64 Mb/s) change in effective data rate results in 67X (18.29 mW to 0.27 mW) change in transmitter power consumption corresponding to only 2X (2.29 mW/Gb/s to 4.24 mW/Gb/s) degradation in energy efficiency for 32-byte long data bursts. We also present an analytical bit error rate (BER) computation technique for this transmitter under rapid on-off operation, which uses MDLL settling measurement data in conjunction with always-on transmitter measurements. This technique indicates that the BER bathtub width for 10^(−12) BER is 0.65 UI and 0.72 UI during rapid on-off operation and always-on operation, respectively. Next, a pulse response estimation-based technique is proposed enabling burst-mode operation for baud-rate sampling receivers that operate over high loss channels. Such receivers typically employ discrete time equalization to combat inter-symbol interference. Implementation details are provided for a receiver chip, fabricated in 65nm CMOS technology, that demonstrates efficacy of the proposed technique. A low complexity pulse response estimation technique is also presented for low power receivers that do not employ discrete time equalizers. We also present techniques for implementation of highly digital fractional-N PLL employing a phase interpolator based fractional divider to improve the quantization noise shaping properties of a 1-bit ∆Σ frequency-to-digital converter. Fabricated in 65nm CMOS process, the prototype calibration-free fractional-N Type-II PLL employs the proposed frequency-to-digital converter in place of a high resolution time-to-digital converter and achieves 848 fs rms integrated jitter (1 kHz-30 MHz) and -101 dBc/Hz in-band phase noise while generating 5.054 GHz output from 31.25 MHz input

Design and analysis of adaptively modulated optical orthogonal frequency division multiple access multiband passive optical networks

The aim of this thesis is to explore innovative technical solutions of utilising Optical Orthogonal Frequency Division Multiplexing (OOFDM) in intensity modulation and direct detection (IMDD) based future access networks to provide multi-service capability with a minimum 1 Gb/s per user. This thesis extensively investigates and analyses the feasibility and performance of adaptively modulated optical orthogonal frequency division multiplexing multiple access passive optical networks (AMOOFDMA PONs) upstream transmission systems by numerically simulating AMOOFDMA PONs using experimentally determined parameters. OOFDM transceivers incorporating reflective semiconductor optical amplifiers (RSOAs) and distributed feedback (DFB) lasers are utilised in the transceivers and intensity modulation and direct detection (IMDD) transmission systems are also employed to achieve a low complexity, high speed and large bandwidth PON as a solution for next generation access networks. Numerical simulations has also being undertaken to improve overall AMOOFDMA PON performance and power budget by incorporating optical band-pass filters (OBPFs) at the output of optical network units (ONUs). A major challenge of making PONs spectrally efficient has been addressed in this thesis by investigating the AMOOFDMA PON with ONUs on a single upstream wavelength. The performance of the single upstream wavelength AMOOFDMA PON is compared to the multiple wavelength AMOOFDMA PON. Another major challenge in AMOOFDMA PONs namely improving system capacity has also been addressed by implementing multiband transmission in an AMOOFDMA PON. Results show that for a multiple upstream OOFDMA IMDD PON system over 25 km single mode fibre (SMF) can achieve an aggregated data rate of 11.25 Gb/s and the minimum wavelength spacing between ONUs are independent of the number of ONUs. Results also show that a single upstream wavelength AMOOFDMA IMDD PON with multiband incorporated at the ONUs can achieve a aggregated line rate of 21.25 Gb/s over 25 km SMF

Research and technology, 1990: Goddard Space Flight Center

Goddard celebrates 1990 as a banner year in space based astronomy. From above the Earth's obscuring atmosphere, four major orbiting observatories examined the heavens at wavelengths that spanned the electromagnetic spectrum. In the infrared and microwave, the Cosmic Background Explorer (COBE), measured the spectrum and angular distribution of the cosmic background radiation to extraordinary precision. In the optical and UV, the Hubble Space Telescope has returned spectacular high resolution images and spectra of a wealth of astronomical objects. The Goddard High Resolution Spectrograph has resolved dozens of UV spectral lines which are as yet unidentified because they have never before been seen in any astronomical spectrum. In x rays, the Roentgen Satellite has begun returning equally spectacular images of high energy objects within our own and other galaxies

Cutting Edge Nanotechnology

The main purpose of this book is to describe important issues in various types of devices ranging from conventional transistors (opening chapters of the book) to molecular electronic devices whose fabrication and operation is discussed in the last few chapters of the book. As such, this book can serve as a guide for identifications of important areas of research in micro, nano and molecular electronics. We deeply acknowledge valuable contributions that each of the authors made in writing these excellent chapters

Economically sustainable public security and emergency network exploiting a broadband communications satellite

The research contributes to work in Rapid Deployment of a National Public Security and Emergency Communications Network using Communication Satellite Broadband. Although studies in Public Security Communication networks have examined the use of communications satellite as an integral part of the Communication Infrastructure, there has not been an in-depth design analysis of an optimized regional broadband-based communication satellite in relation to the envisaged service coverage area, with little or no terrestrial last-mile telecommunications infrastructure for delivery of satellite solutions, applications and services. As such, the research provides a case study of a Nigerian Public Safety Security Communications Pilot project deployed in regions of the African continent with inadequate terrestrial last mile infrastructure and thus requiring a robust regional Communications Satellite complemented with variants of terrestrial wireless technologies to bridge the digital hiatus as a short and medium term measure apart from other strategic needs. The research not only addresses the pivotal role of a secured integrated communications Public safety network for security agencies and emergency service organizations with its potential to foster efficient information symmetry amongst their operations including during emergency and crisis management in a timely manner but demonstrates a working model of how analogue spectrum meant for Push-to-Talk (PTT) services can be re-farmed and digitalized as a “dedicated” broadband-based public communications system. The network’s sustainability can be secured by using excess capacity for the strategic commercial telecommunication needs of the state and its citizens. Utilization of scarce spectrum has been deployed for Nigeria’s Cashless policy pilot project for financial and digital inclusion. This effectively drives the universal access goals, without exclusivity, in a continent, which still remains the least wired in the world

NASA Tech Briefs, January 1987

Topics include: NASA TU Services; New Product Ideas; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Fabrication Technology; Machinery; Mathematics and Information Sciences; Life Sciences

Technology 2001: The Second National Technology Transfer Conference and Exposition, volume 1

Papers from the technical sessions of the Technology 2001 Conference and Exposition are presented. The technical sessions featured discussions of advanced manufacturing, artificial intelligence, biotechnology, computer graphics and simulation, communications, data and information management, electronics, electro-optics, environmental technology, life sciences, materials science, medical advances, robotics, software engineering, and test and measurement

Space programs summary no. 37-45, volume IV FOR the period April 1, 1967 to May 31, 1967. Supporting research and advanced development

Space exploration projects on systems, guidance and control, environmental simulation, space sciences, propulsion, telecommunications, and engineering mechanic