Timing recovery for two-dimensional modulation codes

Two-dimensional modulation codes were recently introduced as a method of increasing magnetic data storage densities. The authors introduce a timing recovery circuit for use by systems that employ two-dimensional modulation codes. The circuit generalizes the familiar square-and-filter approach. Computer simulations were used to determine the performance of this circuit in terms of peak-to-peak jitter vs. the signal to noise ratio at various pulse densities. Another circuit is proposed to remove relative time-shift from adjacent tracks. This circuit is necessary for proper operation of the timing recovery circuit in systems with removable media