Runout Compensator for Disk File
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-27
This article describes a simple implementation of a feed forward runout compensation circuit useful in reducing repeatable runout errors in the track-following system or focus servo system of an optical disk file, or in the track-following system of a magnetic recording disk file. An integrated implementation of this runout compensator can be constructed with one or two integrated circuits. The figure outlines the essential elements of the circuit. The major components consist of a presettable Binary Counter, a Switched Capacitor Filter, a multiplying digital-to-analog converter (MDAC), a single Analog Comparator, and digital Control Logic. As shown, the system accepts one analog input, the servo runout error signal, and generates one analog output, the servo feed forward error signal.