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Feed Forward Track Following

IP.com Disclosure Number: IPCOM000034831D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27

Publishing Venue

IBM

Related People

Authors:
Baca, FA Chow, WW DeLancey, JL Kadlec, RJ [+details]

Abstract

Track following in optical disk having extremely high track densities is enhanced by profiling the radial run out and compensating the track following servo with information concerning the profiled run out. The profile is time averaged for minimizing the influence of nonrepeatable disturbances, such as noise which occur in the measured profile samples. The greater the noise level, the more significant the time averaging becomes to highly faithful track following. The second aspect is (Image Omitted) to advance the profile in time to compensate for time delays in the servo circuitry. The reason for this time advance is that the analog control signal has a significant high frequency energy as a result of media optical noise and electronic noise, all of which is accentuated by zero compensation circuits.