Abstract: An all digital method and apparatus for recovering NRZ information from MFM data wherein the MFM pulse stream is monitored through hypothetical windows, the receipt of a pulse during a particular window providing information about the data state(s) represented by the pulse and tracking adjustments required to recover subsequent pulses, and further wherein each window is divided into a large number of subinterval's so that the coincidence of a pulse with a particular subinterval provides information about the amount and direction by which the position of subsequent windows should be changed for tracking correction; the windows and subintervals being implemented by the execution of one of a number of step sequences, the particular step sequence being executed indicating the classification of a pulse received during the particular step sequence, and the step being executed at the time of receipt of the pulse indicating required tracking adjustments.