| 摘要 |
A method and an arrangement are provided for synchronizing a receiver into a quadrature amplitude modulated (QAM) signal. The receiver comprises a first controllable unit ( 601 ) arranged to respond to a timing control signal by controlling the timing by which a received signal is converted into demodulated complex samples. Additionally it comprises a symbol detector ( 603 ) arranged to produce, in correspondence with the complex samples, a detection decision (s) that represents a received symbol. There are elements ( 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, 602 ) for generating one or more complex baseband equivalent impulse response values for a QAM-channel as a correlation result by correlating complex demodulated samples with a complex correlation variable (C) derived from the detection decision (s). The sensitivity to changes caused by cables rotating the baseband equivalent impulse response and by the unknown phase difference between the transmitter upmodulator and the receiver demodulator is deleted by appropriate postprocessing of the correlation results. The timing control signal is derived from the postprocessed correlation results.
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