7,595 research outputs found

    Communications techniques and equipment: A compilation

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    This Compilation is devoted to equipment and techniques in the field of communications. It contains three sections. One section is on telemetry, including articles on radar and antennas. The second section describes techniques and equipment for coding and handling data. The third and final section includes descriptions of amplifiers, receivers, and other communications subsystems

    A synchronised Direct Digital Synthesiser

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    We describe a Direct Digital Synthesiser (DDS) which provides three frequency-locked synchronised outputs to generate frequencies from DC to 160 MHz. Primarily designed for use in a heterodyning range imaging system, the flexibility of the design allows its use in a number of other applications which require any number of stable, synchronised high frequency outputs. Frequency tuning of 32 bit length provides 0.1 Hz resolution when operating at the maximum clock rate of 400 MSPS, while 14 bit phase tuning provides 0.4 mrad resolution. The DDS technique provides very high relative accuracy between outputs, while the onboard oscillator’s stability of ±1 ppm adds absolute accuracy to the design

    Development Of Inductively-Degenerated LNA For W-CDMA Application Utilizing 0.18 Um RFCMOS Technology

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    Satu metodologi terperinci dan bersistematik untuk merekabentuk penguat hingar rendah (LNA) induktif ternyahjana kaskod, juga dikenali sebagai topologi Padanan Masukan dan Hingar Serentak (SNIM), A detailed and systematic methodology on the design of the inductivelydegenerated cascode LNA, also known as the Simultaneously Noise and Input Matching (SNIM) LNA

    A Low Power 5.8GHz Fully Integrated CMOS LNA for Wireless Applications

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    A low power 5.8 GHz fully integrated CMOS low noise amplifier (LNA) with on chip spiral inductors for wireless applications is designed based on TSMC 0.18 µm technology in this paper. The cascode structure and power-constrained simultaneous noise and input matching technique are adopted to achieve low noise, low power and high gain characteristics. The proposed LNA exhibit a state of the art performance consuming only 6.4mW from a 1.8V power supply. The simulation results show that it has a noise figure (NF) only 0.972 dB, which is perfectly close to NFmin while maintaining the other performances. The proposed LNA also has an input 1-dB compression point (IP1dB) of-21.22 dBm, a power gain of 17.04 dB, and good input and output reflection coefficients, which indicate that the proposed LNA topology is very suitable for the implementation of narrowband LNAs in 802.11a wireless applications

    Adaptive multibeam antennas for spacelab. Phase A: Feasibility study

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    The feasibility was studied of using adaptive multibeam multi-frequency antennas on the spacelab, and to define the experiment configuration and program plan needed for a demonstration to prove the concept. Three applications missions were selected, and requirements were defined for an L band communications experiment, an L band radiometer experiment, and a Ku band communications experiment. Reflector, passive lens, and phased array antenna systems were considered, and the Adaptive Multibeam Phased Array (AMPA) was chosen. Array configuration and beamforming network tradeoffs resulted in a single 3m x 3m L band array with 576 elements for high radiometer beam efficiency. Separate 0.4m x 0.4 m arrays are used to transmit and receive at Ku band with either 576 elements or thinned apertures. Each array has two independently steerable 5 deg beams, which are adaptively controlled

    A High Stability Optical Shadow Sensor with Applications for Precision Accelerometers

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    Gravimeters are devices which measure changes in the value of the gravitational acceleration, \textit{g}. This information is used to infer changes in density under the ground allowing the detection of subsurface voids; mineral, oil and gas reserves; and even the detection of the precursors of volcanic eruptions. A micro-electro mechanical system (MEMS) gravimeter has been fabricated completely in silicon allowing the possibility of cost e-effective, lightweight and small gravimeters. To obtain a measurement of gravity, a highly stable displacement measurement of the MEMS is required. This requires the development of a portable electronics system that has a displacement sensitivity of 2.5\leq 2.5 nm over a period of a day or more. The portable electronics system presented here has a displacement sensitivity 10\leq 10 nm/Hz/\sqrt{\textrm{Hz}} (0.6\leq 0.6 nm at 10001000 s). The battery power system used a modulated LED for measurements and required temperature control of the system to ±\pm 2 mK, monitoring of the tilt to ±\pm 2 μ\muradians, the storage of measured data and the transmission of the data to an external server.Comment: 8 Pages, 12 figures, 5 equations, currently submitted and under review at IEEE Sensors SIE

    Concepts for 18/30 GHz satellite communication system, volume 1

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    Concepts for 18/30 GHz satellite communication systems are presented. Major terminal trunking as well as direct-to-user configurations were evaluated. Critical technologies in support of millimeter wave satellite communications were determined
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