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High Track Density Servo Position Error Signal Processing

IP.com Disclosure Number: IPCOM000041392D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02

Publishing Venue

IBM

Related People

Authors:
Liu, CC [+details]

Abstract

Described here is a novel method for processing servo position error signals (PES) in disk file applications. It is applicable to certain classes of PES systems having two separated and yet related PES output signals. Their output vs. head displacement characteristics must be identical, except one is shifted from the other by an amount of one track pitch. An electronic linear operation of 'summing' and 'difference' is applied to the PES outputs. As a result of the operation, new signals are generated such that they exhibit the following unique properties: (1) higher track density, (2) quadrature PES, and (3) larger PES gain linear range. Fig. 1 shows a pair of the PES outputs (A,B) from a servo system employing a tetra-orthogonal servo encodement.