QAM receiver with quadrature error correction - uses decision error for in=phase and quadrature components to calculate error correction value

摘要

The receiver has a coefficient weighting circuit for weighting the in-phase and quadrature components of the received signal with respective coefficients dependent on the quadrature error. A correction circuit (KS) uses the decision errors (eI, eQ) of the in-phase and quadrature signal values to provide a correction value (Qs) for the quadrature error from the decision error gradients. Pref. the in-phase and quadrature components and the decision errors are combined via multipliers, adders and sign function operators to provide the correction value. ADVANTAGE - Simple circuit providing exact correction of quadrature error.