Title :
A performance comparison of 16 QAM digital PLL based demodulators
Author :
Chen, Albert Y. ; Fitz, Michael P. ; Sethare, W.A.
Author_Institution :
Delco Electron. Corp., Kokomo, IN, USA
Abstract :
A quantitative assessment of acquisition performance and a unified comparison of all the proposed carrier synchronization structures for QAM is missing from the literature. This paper is an attempt to provide that analysis and performance comparison. It presents statistical characterizations of several digitally implemented, uniformly sampled, first-order PLLs for QAM modulation. Since a majority of the phase detectors used in QAM modulation are discrete time (e.g., decision directed) in nature, the digital PLL (DPLL) is the natural implementation of these carrier synchronization loops. The first-order DPLL when the modulation is an i.i.d. random sequence and when operating in the additive white Gaussian noise channel (AWGN) produces a phase estimate that is a discrete time first-order Markov process, and the many tools for Markov analysis can be brought to bear on the performance analysis
Keywords :
Gaussian channels; Markov processes; demodulation; demodulators; digital phase locked loops; quadrature amplitude modulation; synchronisation; 16 QAM digital PLL; AWGN; IID random sequence; Markov analysis; acquisition performance; additive white Gaussian noise channel; carrier synchronization loop; carrier synchronization structures; decision directed processing; demodulators; digital PLL; digital first-order PLL; discrete time detectors; discrete time first-order Markov process; performance analysis; performance comparison; phase detectors; phase estimate; statistical characteristics; uniformly sampled DPLL; AWGN; Demodulation; Detectors; Digital modulation; Performance analysis; Phase detection; Phase locked loops; Phase modulation; Quadrature amplitude modulation; Random sequences;
Conference_Titel :
Global Telecommunications Conference, 1994. GLOBECOM '94. Communications: The Global Bridge., IEEE
Print_ISBN :
0-7803-1820-X
DOI :
10.1109/GLOCOM.1994.513554
