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Inventi Impact: Reconfigurable Computing

Articles

  • Inventi:erc/15080/15
    FPGA-Based Implementation of All-Digital QPSK\nCarrier Recovery Loop Combining Costas Loop and\nMaximum Likelihood Frequency Estimator
    01-Jan-1970 Research 2015 : January - March
    Kaiyu Wang, Zhiming Song, Xianwei Qi, Qingxin Yan, Zhenan Tang

    This paper presents an efficient all digital carrier recovery loop (ADCRL) for quadrature phase shift keying (QPSK). The ADCRL\ncombines classic closed-loop carrier recovery circuit, all digital Costas loop (ADCOL), with frequency feedward loop, maximum\nlikelihood frequency estimator (MLFE) so as to make the best use of the advantages of the two types of carrier recovery loops and\nobtain amore robust performance in the procedure of carrier recovery. Besides, considering that, for MLFE, the accurate estimation\nof frequency offset is associated with the linear characteristic of its frequency discriminator (FD), the Coordinate Rotation Digital\nComputer (CORDIC) algorithm is introduced into the FDbased on MLFE to unwrap linearly phase difference.The frequency offset\ncontained within the phase difference unwrapped is estimated by the MLFE implemented just using some shifter and multiplyaccumulate\nunits to assist the ADCOL to lock quickly and precisely. The joint simulation results ofModelSim andMATLAB show\nthat the performances of the proposed ADCRL in locked-in time and range are superior to those of the ADCOL. On the other\nhand, a systematic design procedure based on FPGA for the proposed ADCRL is also presented

    How to Cite this Article
    CC Compliant Citation: Kaiyu Wang, Zhiming Song, Xianwei\nQi, Qingxin Yan, and Zhenan Tang, â??FPGA-Based\nImplementation of All-Digital QPSK Carrier Recovery Loop\nCombining Costas Loop and Maximum Likelihood Frequency\nEstimator,â? International Journal of Reconfigurable\nComputing, vol. 2014, Article ID 502942, 15 pages, 2014.\ndoi:10.1155/2014/502942, http://creative commons.org/\nlicenses/by/3.0/.
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