Data systems elements technology assessment and system specifications, issue no. 2

The ability to satisfy the objectives of future NASA Office of Applications programs is dependent on technology advances in a number of areas of data systems. The hardware and software technology of end-to-end systems (data processing elements through ground processing, dissemination, and presentation) are examined in terms of state of the art, trends, and projected developments in the 1980 to 1985 timeframe. Capability is considered in terms of elements that are either commercially available or that can be implemented from commercially available components with minimal development

Front-ends para LiDAR baseados em ADC e TDC

Autonomous vehicles are a promising technology to save over a million lives each year that are lost in road accidents. However, bringing safe autonomous vehicles to market requires massive development, starting with vision sensors. LiDAR is a fundamental vision sensor for autonomous vehicles, as it enables high resolution 3D vision. However, automotive LiDAR is not yet a mature technology, and, also requires massive development in many aspects. This thesis aims to contribute to the maturity of LiDAR, focusing on sampling architectures for LiDAR front-ends. Two architectures were developed. The first is based on a pipelined ADC, available from an AD-FMCDAQ2-EBZ board. The ADC is synchronized with the emitted pulse and able to sample at 1 Gsample/s. The second architecture is based on a TDC that is directly implemented in an FPGA. It relies on a tapped delay line topology comprising 45 delay elements and on a mux-based decoder, resulting in a resolution of 50 ps. Preliminary test results show that both implementations operate correctly, and are both suitable for sampling short pulses typically used by LiDARs. When comparing both architectures, we conclude that an ADC consumes a significant amount of power, and uses many FPGA resources. However, it samples the LiDAR waveform without any loss of information, therefore enabling maximum range and precision. The TDC is just the opposite: it consumes little power, and uses less FPGA resources. However, it only captures one sample per pulse.Os veículos autónomos são uma tecnologia promissora para salvar mais de um milhão de vidas por ano, colhidas por acidentes rodoviários. Contudo, colocar veículos autónomos seguros no mercado requer inúmeros desenvolvimentos, a começar por sensores de visão. O LiDAR é um sensor de visão fundamental para veículos autónomos, pois permite uma visão 3D de alta resolução. Contudo, o LiDAR automotivo não é uma tecnologia madura, e portanto requer também desenvolvimento em vários aspectos. Esta dissertação visa contribuir para a maturidade do LiDAR, com foco em arquiteturas de amostragem para front-ends de LiDAR. Foram desenvolvidas duas arquiteturas. A primeira assenta numa ADC pipelined, por sua vez implementada numa placa de teste AD-FMCDAQ2-EBZ. A ADC opera em sincronismo com o pulso emitido, e permite capturar amostras a 1 Gsample/s. A segunda arquitetura assenta num TDC implementado diretamente numa FPGA. O TDC baseia-se numa topologia tapped delay line com 45 linhas de atraso, e num descodificador à base de multiplexers, permitindo uma resolução temporal de 50 ps. Resultados preliminares mostram que ambas as implementações operam corretamente, e são adequadas para amostrar pulsos curtos tipicamente associados a LiDAR. Em termos comparativos, a arquitectura com base numa ADC tem um consumo de potência considerável e requer uma quantidade significativa de recursos da FPGA. Contudo, esta permite amostrar a forma de onda de LiDAR sem nenhuma perda de informação, permitindo assim alcance e precisão máximos. A arquitectura com base num TDC é exatamente o oposto: tem um baixo consumo de potência e requer poucos recursos da FPGA. Contudo, permite capturar apenas uma amostra por pulso.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Architectures of new switching systems.

by Lam Wan.Thesis submitted in: November 1997.Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.Includes bibliographical references (leaves 96-102).Abstract also in Chinese.Part IChapter 1 --- Introduction to Integrated Intelligent Personal Communication System --- p.1Chapter 2 --- The Switching Architecture --- p.5Chapter 2.1 --- The Overall Switching Architecture --- p.6Chapter 2.2 --- Switching Module --- p.10Chapter 2.2.1 --- Traffic Routing in Switching Module --- p.11Chapter 2.2.2 --- Structure of Switching Module --- p.15Chapter 2.2.3 --- Wireless Base Interface --- p.16Chapter 2.2.4 --- Trunk Interface --- p.18Chapter 2.2.5 --- Analog Interfaces --- p.18Chapter 2.3 --- Network Intelligence --- p.19Chapter 2.4 --- Wireless Part --- p.21Chapter 2.4.1 --- Call-Setup in IIPCS --- p.24Chapter 2.4.2 --- Handoff --- p.25Chapter 2.4.3 --- Wireless Base --- p.27Chapter 2.5 --- Downstream Wired Extensions --- p.28Chapter 2.6 --- Upstream Wired Part --- p.28Chapter 2.7 --- Voice System --- p.28Chapter 2.8 --- Features of the IIPCS --- p.29Chapter 3 --- Concluding Remarks --- p.33Chapter 3.1 --- Summary --- p.35Chapter 3.2 --- Directions for Further Research --- p.36Part IIChapter 4 --- Introduction to Next-Generation Switch --- p.37Chapter 5 --- Architecture of Next-Generation Switch --- p.41Chapter 5.1 --- Overall Architecture of Next-Generation Switch --- p.42Chapter 5.1.1 --- Interface module --- p.44Chapter 5.1.2 --- Packetizer --- p.46Chapter 5.2 --- Concentration Fabric --- p.50Chapter 5.3 --- Shared-Buffer Memory Switch --- p.53Chapter 6 --- Concentration Networks --- p.56Chapter 6.1 --- Background of Concentration Networks --- p.56Chapter 6.2 --- k-Sorting --- p.63Chapter 6.3 --- Concentrator --- p.72Chapter 6.3.1 --- Nk-to-k Concentrator --- p.73Chapter 6.3.2 --- Match between Circles with Cost Reduction --- p.75Chapter 6.4 --- The Structure of a Molecule --- p.78Chapter 6.5 --- Summary --- p.81Chapter 7 --- Lock-Latch Algorithm --- p.82Chapter 8 --- Performance Evaluation --- p.88Chapter 9 --- Concluding Remarks --- p.93Chapter 9.1 --- LSI Implementation --- p.94Chapter 9.2 --- Summary --- p.95Bibliograph

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

Proceedings of the Mobile Satellite Conference

A satellite-based mobile communications system provides voice and data communications to mobile users over a vast geographic area. The technical and service characteristics of mobile satellite systems (MSSs) are presented and form an in-depth view of the current MSS status at the system and subsystem levels. Major emphasis is placed on developments, current and future, in the following critical MSS technology areas: vehicle antennas, networking, modulation and coding, speech compression, channel characterization, space segment technology and MSS experiments. Also, the mobile satellite communications needs of government agencies are addressed, as is the MSS potential to fulfill them