| 摘要 |
Apparatus (100) is described comprising: an antenna array (1021 . . . 102N); a plurality of units (1041 . . . 104N), each unit configured to mix a radio frequency signal from one or more of the antennas (102) with oscillating signals having phases defined by a global signal and to provide in-phase and quadrature-phase signals; a constellation rotation system configured to, for each unit, rotate a constellation point associated with the in-phase and quadrature-phase signals by a rotation angle to provide adjusted in-phase and quadrature-phase signals; signal buses (106, 107) for global in-phase and quadrature-phase signals configured to receive the adjusted in-phase and quadrature-phase signals, respectively, from a plurality of the units; a feedback system configured to, for each unit, compare one or more of the adjusted in-phase and quadrature-phase signals with one or more of the global in-phase and quadrature-phase signals to determine an error in the rotation angle. |
