TIMING SYNCHRONIZATION AND PHASE/FREQUENCY CORRECTION OF QPSK SIGNALS

A method and apparatus for digitally demodulating QPSK signals includes a first portion in which the digitally sampled data burst is resampled with a plurality of predetermined timing hypotheses. The timing offset is determine d according to an analysis of the resampled data. The digitally sampled d...

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Bibliographische Detailangaben
Hauptverfasser:	LEIGH, WILLIAM E. L, BECKER, DONALD W
Format:	Patent
Sprache:	eng ; fre
Schlagworte:	BASIC ELECTRONIC CIRCUITRY CALCULATING COMPUTING COUNTING ELECTRIC COMMUNICATION TECHNIQUE ELECTRIC DIGITAL DATA PROCESSING ELECTRICITY PHYSICS PICTORIAL COMMUNICATION, e.g. TELEVISION SELECTING RESONANT CIRCUITS TRANSMISSION TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION TUNING RESONANT CIRCUITS
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Beschreibung
Zusammenfassung:	A method and apparatus for digitally demodulating QPSK signals includes a first portion in which the digitally sampled data burst is resampled with a plurality of predetermined timing hypotheses. The timing offset is determine d according to an analysis of the resampled data. The digitally sampled data burst is then resampled according to the timing estimation. Modulation of th e resampled data burst is then removed by twice squaring the complex I/Q pairs . The data with the modulation removed is then subjected to a Chirp-Z Transfor m to move the data into the frequency domain. The highest spectral power is us ed to determine the frequency offset. The phase offset is determined and the resampled data burst is derotated and dephased according to the phase offset and the frequency offset.