Marconi Communications Gmbh

Telefonaktiebolaget Lm Ericsson (publ)

Gerhard Peter Herbig

Thomas Gebauer

Michael Biester

A symbol-timing recovery function of a receiver is provided with a signal combiner () coupled to a first receive branch with a first receive signal () and to a second receive branch with a second receive signal (). The signal combiner () generates a combined signal (C) on the basis of the first receive signal () and the second receive signal (). Further, a common timing error detector (C) is provided. The common timing error detector (C) is coupled to the signal combiner () and is configured to generate a common timing error signal (TEC) on the basis of the combined signal. A first digital symbol timing for the first receive signal () and a second digital symbol timing for the second receive signal () are recovered on the basis of the common timing error signal (TEC).

Symbol-timing recovery techniques for multi-branch receivers

The invention relates to a phase error detector which generates a phase correction signal in such a manner that the phase characteristic curve thereof does not have any undesired zero positions and comprises a finite steepness in the angular area around the engaging point. The inventive phase error detector (PFD) calculates the phase correction signal (S) according to the detected decision domain in accordance with a number of predetermined calculating methods. The phase error detector (PFD) attains such an allocation between the decision domains of the complex QAM single state plane and the individual calculating methods such that the static phase characteristic curve thereof does not have any additional zero positions apart from the engaging point.

Phase error detector for a quadrature amplitude modulated (QAM) receiver

The inventive receiver has a receiving branch for each of the two signals (EH, EV) and a demodulator (MHE, MVE) and means (SH, SV) for synchronising the phase of the received signal (EH, EV) with the transmitting phase are provided in said branches, respectively. Polaristion decouplers (XPIC-VH, XPIC-HV) which compensate cross-polar crosstalk between the two received signals (EH, EV) are provided for both of the receiving branches. The polarisation decoupling (XPIC-VH, XPIC-HV) of the two received signals (EH, EV) takes place after they have been demodulated (MHE, MVE) and before they have been phase-synchronised (SH, SV) so that the receiver can function as inexpensively as possible in terms of the components that it requires and so that it can also compensate cross polar channel crosstalk for circular QAM signal constellations.

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Oppenweiler, Germany

Gerhard Peter Herbig