International Business Machines Corporation

Paul J Dounn

Karl Arnold Belser

Richard C Schneider

Morovat B Tayefeh

Ian E Henderson

Spencer D Roberts

Ronald J Kadlec

Terry L Kise

In a recordable media drive, error processing is implemented in an adjustable read channel equalizer in which gain and bandwidth values can be selectively adjusted. In a write/verify procedure, the gain value is reduced, while the bandwidth is increased, thereby stressing the read channel during verification of written sectors in order to force the failure of marginal sectors. In an error recovery procedure, when a sector error is encountered, the gain value of the adjustable equalizer is initially increased and a sequence of read retries of the failed sector is initiated.

Adjustable read channel equalization for error processing in a

A track-seeking system for an optical disk using a velocity control loop with partially-digitized velocity measurement. A quadrature signal is generated based on summing the halves of a position error signal to give directionality to track-crossing counts. A so-called piggy-back construction, wherein a fine positioner is carried by a coarse positioner, is employed. Feed-forward controls are provided from the fine to the coarse positioner. At track-capture time, the dynamic range of the fine positioner is momentarily increased.

Transducer positioning servo mechanisms employing digital and analog

Growing community of inventors

Tucson, AZ, United States of America

Paul J Dounn