81 research outputs found

    Performance Enhancement of Coherent Optical OFDM System Using LMS Algorithm, Journal of Telecommunications and Information Technology, 2020, nr 4

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    Instability of the local oscillator causes phase noise – a phenomenon that is a disadvantage and is considered to be a major obstacle in the functioning of coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. An attempt has been made in this paper to reduce the effects of common phase errors generated by phase noise. In this paper, a least mean square (LMS) based algorithm is proposed for estimation of phase noise. Using this proposed algorithm, the major problem of phase ambiguity caused by cycle slip is avoided and the bit error rate is greatly improved. Further, there is no requirement for modifying the frame structure of OFDM using this algorithm. A CO-OFDM system with the 8-PSK technique is used to implement the algorithm concerned. Furthermore, the algorithm, using the 8-PSK modulation technique, is analyzed and compared with the existing QPSK technique and with other algorithms. The investigations reveal that 8-PSK outperforms existing LMS algorithms using other techniques and significantly reduces the bit error rate

    The Telecommunications and Data Acquisition

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    This quarterly publication provides archival reports on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA). In space communications, radio navigation, radio science, and ground-based radio and radar astronomy, it reports on activities of the Deep Space Network (DSN) in planning, supporting research and technology, implementation, and operations. Also included are standards activity at JPL for space data and information systems and reimbursable DSN work performed for other space agencies through NASA. The preceding work is all performed for NASA's Office of Space Communications (OSC)

    Engineering evaluations and studies. Volume 3: Exhibit C

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    High rate multiplexes asymmetry and jitter, data-dependent amplitude variations, and transition density are discussed

    Space programs summary no. 37-58, volume 3 for the period 1 June - 31 July 1969. Supporting research and advanced development

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    Review of developments in current engineering and scientific work at JP

    Deep Space Telecommunications Systems Engineering

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    Descriptive and analytical information useful for the optimal design, specification, and performance evaluation of deep space telecommunications systems is presented. Telemetry, tracking, and command systems, receiver design, spacecraft antennas, frequency selection, interference, and modulation techniques are addressed

    Space programs summary no. 37-64, volume 2 for the period 1 June to 31 July 1970. The Deep Space Network

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    Mariner Mars 1971 mission support, engineering, and design of Deep Space Networ

    The deep space network

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    A report is given of the Deep Space Networks progress in (1) flight project support, (2) tracking and data acquisition research and technology, (3) network engineering, (4) hardware and software implementation, and (5) operations

    Tracking and data system support for the Viking 1975 mission to Mars. Volume 1: Prelaunch planning, implementation, and testing

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    The tracking and data acquisition support for the 1975 Viking Missions to Mars is described. The history of the effort from its inception in late 1968 through the launches of Vikings 1 and 2 from Cape Kennedy in August and September 1975 is given. The Viking mission requirements for tracking and data acquisition support in both the near earth and deep space phases involved multiple radar tracking and telemetry stations, and communications networks together with the global network of tracking stations, communications, and control center. The planning, implementation, testing and management of the program are presented

    Voyager spacecraft system. Volume A - Preferred design for flight spacecraft and hardware subsystems, part II Final technical report

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    Subsystems development in proposed Voyager spacecraft desig

    The deep space network

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    The objectives, functions, and organization of the Deep Space Network are summarized. Deep space station, ground communication, and network operations control capabilities are described
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