Systems and techniques relating to interpreting signals on a noisy channel. A direct current (DC) correction can be applied to an input of a post processor outside of a main read path that supplies data detector output to the post processor. A signal processor, such as a read channel transceiver device usable in a magnetic recording system, has a main read path including a signal equalizer and a data detector. A post processor is responsive to the output of the data detector, and a DC control unit applies a DC correction to an input of the post processor outside of the main read path.