An adaptive equalizer for partial response magnetic recording channels

The application of two adaptive equalizers to a digital magnetic recording channel is discussed. The memoryless decision-directed equalizer for a Class IV partial response signal is described. The more complex block equalizer is then presented. Taking advantage of the Class IV partial response signal characteristics, a block estimate of K channel input symbols is used to calculate an update for the equalizer coefficients. Through computer simulations of untrained adaptation, the mean-squared error performance of the block equalizer and the decision-directed equalizer is compared. The mean-squared error of the block equalizer is shown to converge toward the minimum at a faster rate for the simulated channel conditions