923 research outputs found

    Mobile terminal equipment design utilising split-loop phase-lock techniques

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    The design and resultant performance of the terminal equipment in a mobile satellite system is vitally important in respect to the overall cost/performance compromise of the whole system. Improvements in system performance which also result in a reduction of the equipment cost are rare. However, this paper details a significant advance in terminal design, utilizing a novel form of 'split-loop' phase locked receiver/downconverter system to enable an accurate, stable and wide coverage terminal to be realized at a reduced cost. The system has the capability of automatically locking onto any carrier within a complete transponder, and can cope with severe amplitude modulation and fading effects

    Study of state-of-the-art static inverter design Final report, 6 Jan. - 6 Jun. 1966

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    Multiple purpose inverter design based on phase demodulated inverter circuit selected from state-of-the-art assessment of ten inverter circuit

    Frequency shift keying apparatus Patent

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    Frequency shift keying apparatus for use with pulse code modulation data transmission syste

    Digital demodulator-correlator

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    An apparatus for demodulation and correlation of a code modulated 10 MHz signal is presented. The apparatus is comprised of a sample and hold analog-to-digital converter synchronized by a frequency coherent 40 MHz pulse to obtain four evenly spaced samples of each of the signal. Each sample is added or subtracted to or from one of four accumulators to or from the separate sums. The correlation functions are then computed. As a further feature of the invention, multipliers are each multiplied by a squarewave chopper signal having a period that is long relative to the period of the received signal to foreclose contamination of the received signal by leakage from either of the other two terms of the multipliers

    Study of a navigation and traffic control technique employing satellites. Volume 3 - User hardware Interim report

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    User hardware configurations and requirements for navigation and air traffic control technique using satellite

    The Deep Space Network: A Radio Communications Instrument for Deep Space Exploration

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    The primary purpose of the Deep Space Network (DSN) is to serve as a communications instrument for deep space exploration, providing communications between the spacecraft and the ground facilities. The uplink communications channel provides instructions or commands to the spacecraft. The downlink communications channel provides command verification and spacecraft engineering and science instrument payload data

    Modeling and analysis of power processing systems: Feasibility investigation and formulation of a methodology

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    A review is given of future power processing systems planned for the next 20 years, and the state-of-the-art of power processing design modeling and analysis techniques used to optimize power processing systems. A methodology of modeling and analysis of power processing equipment and systems has been formulated to fulfill future tradeoff studies and optimization requirements. Computer techniques were applied to simulate power processor performance and to optimize the design of power processing equipment. A program plan to systematically develop and apply the tools for power processing systems modeling and analysis is presented so that meaningful results can be obtained each year to aid the power processing system engineer and power processing equipment circuit designers in their conceptual and detail design and analysis tasks

    A direct-sequence spread-spectrum super-regenerative receiver

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    Current applications of the super-regenerative receiver use narrowband modulations. In this paper a new architecture that allows incoherent detection of spread-spectrum signals is presented. A pseudorandom code generator has been added to the original circuit. It is clocked by the quench oscillator and takes advantage of the characteristic broad reception bandwidth. CDMA can be achieved via ASK and FSK modulated signals with high simplicity in the RF stage as well as low power consumption.Peer ReviewedPostprint (published version

    Breadboard linear array scan imager using LSI solid-state technology

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    The performance of large scale integration photodiode arrays in a linear array scan (pushbroom) breadboard was evaluated for application to multispectral remote sensing of the earth's resources. The technical approach, implementation, and test results of the program are described. Several self scanned linear array visible photodetector focal plane arrays were fabricated and evaluated in an optical bench configuration. A 1728-detector array operating in four bands (0.5 - 1.1 micrometer) was evaluated for noise, spectral response, dynamic range, crosstalk, MTF, noise equivalent irradiance, linearity, and image quality. Other results include image artifact data, temporal characteristics, radiometric accuracy, calibration experience, chip alignment, and array fabrication experience. Special studies and experimentation were included in long array fabrication and real-time image processing for low-cost ground stations, including the use of computer image processing. High quality images were produced and all objectives of the program were attained

    Mariner mars 1964 telemetry and command system

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    Telemetry and command system for Mariner-Mars 1964 missio
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