An experimental sector servo system for a rotary head tape recorder

Track registration marks (TRMs) are recorded on the data tracks to measure head-to-track registration with high accuracy in a D2 video production recorder. An experimental sector servo uses a controller structure which generates an internal model of the track shape based on these measurements and cancels the repeatable tracking error. A sector servo system was implemented using four TRMs along each track. A total of 12 TRMs was recorded, to monitor the track position in between sampling points. The standard deviation of the residual error is 0.735 μm. Since track curvature errors are effectively eliminated, the experiment suggests that the excess head width (and hence track width) could be reduced by a factor of three or four without detrimental effects on data recovery due to mistracking