In an automatic phase alignment circuit for a Cartesian feedback amplifier, the phase error is regularly monitored. In various implementations, this approach is used to provide true and continuous phase alignment. Based on a relationship between the up-converted and down-converted signals, another implementation of the invention provides phase-alignment for quadrature-phase components of a baseband signal by arithmetically combining the quadrature-phase components and the feedback components continuously and, in response, continuously phase-adjusting signals in the feed-forward signal path. Another aspect of the present invention is directed to an approach for calculating phase error for that is caused by DC-offset interference which, in turn, manifest at the outputs of many analog functional blocks.