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HEAD-POSITIONING ERROR SIGNAL GENERATOR for MAGNETIC DISK DRIVE

IP.com Disclosure Number: IPCOM000040104D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Arai, K: AUTHOR

Abstract

In a magnetic small disk drive wherein the data track is accessed using a head drive motor equipped with an encoder which produces pseudo sine- wave encoder signals of one cycle per track, the encoder signals are uniquely combined to form plural composite signals which are selectively switched to form a substantially sawtoothed head positioning error signal. This signal can be used to precisely position the magnetic head in the conventional manner. (Image Omitted) Referring to Fig. 1(A), two phases of the pseudo sine-wave encoder signals are shown in which the B phase signal Vb crosses a reference voltage Vc (e.g., 5V) at a track position T. The A phase signal Va is shifted with a constant voltage Vr (e.g., 2V) to form two kinds of voltage signals of Va+Vr and 10-(Va+Vr), as shown in Fig. 1(B).

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HEAD-POSITIONING ERROR SIGNAL GENERATOR for MAGNETIC DISK DRIVE

In a magnetic small disk drive wherein the data track is accessed using a head drive motor equipped with an encoder which produces pseudo sine- wave encoder signals of one cycle per track, the encoder signals are uniquely combined to form plural composite signals which are selectively switched to form a substantially sawtoothed head positioning error signal. This signal can be used to precisely position the magnetic head in the conventional manner.

(Image Omitted)

Referring to Fig. 1(A), two phases of the pseudo sine-wave encoder signals are shown in which the B phase signal Vb crosses a reference voltage Vc (e.g., 5V) at a track position T. The A phase signal Va is shifted with a constant voltage Vr (e.g., 2V) to form two kinds of voltage signals of Va+Vr and 10-(Va+Vr), as shown in Fig. 1(B). These signals and the B phase signal Vb are selectively switched at points of +45 degrees and +180 degrees from the track position to form the head- positioning error signals of the substantially sawtoothed wave so that the signal is composed of the 10-(Va+Vr) signal between the points of -180 degrees and -45 degrees, Vb signal between the points of -45 degrees and +45 degrees, and Va+Vr signal between the points of +45 degrees and +180 degrees, as shown in Fig. 1(C). To assure smooth switching of the signals at the points of +45 degrees even if the switching point is varied due to the tolerance of parts, 1.2...