Shift error correcting modulation codes

5A class of codes that perform bit-shift error detection/correction directly on run-length-limited (RLL) binary channel data is described. These highly efficient, variable-rate codes can be used with RLL sequences having d,k constraints of d>0 and (k-d)⩾2, and they are fully compatible with conventional signal processing, e.g., peak detection can be used. The simplest and most efficient of these codes are effective only against bit-shift error, i.e., the predominant type of channel data error caused by intersymbol interference and noise in saturation recording systems that employ RLL modulation coding