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Track Following and Seeking System

IP.com Disclosure Number: IPCOM000078790D
Original Publication Date: 1973-Mar-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Spruth, W: AUTHOR [+2]

Abstract

This system comprises a disc pack 1 with one disc 2 carrying a single circular servo track 3 arranged among the data tracks. No special servo disc is needed in this system. Servo signals reproduced by stationary servo transducer 4 actuate voice coil motor 5 of carriage 6, and are compensated by signals of linear positioning device 7 which also controls access to selected data tracks.

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Track Following and Seeking System

This system comprises a disc pack 1 with one disc 2 carrying a single circular servo track 3 arranged among the data tracks. No special servo disc is needed in this system. Servo signals reproduced by stationary servo transducer 4 actuate voice coil motor 5 of carriage 6, and are compensated by signals of linear positioning device 7 which also controls access to selected data tracks.

Servo transducer 4 is fixed on arm 8 and rigidly connected to base 9 of the system. Data transducers 10 are mounted on arms 11 of carriage 6, which is connected to voice coil motor 5 by push rod 12 for radial displacement.

Rigidly connected to rod 12 is transparent scale 13 carrying in a first line, equidistant markings corresponding to the radial distance of the data tracks, and in a second line finely spaced servo markings to compensate deviations. A similar scale 14 with track markings 15 in a first line and servo markings 16 in a second line, is permanently mounted on base 9 and faces scale 13.

Light from light source 17 passes through scales 13, 14 and activates photodiodes 18, 19. Signals from diode 18, indicating the coarse positioning of data transducers 10 relative to the data tracks, are evaluated in circuit 20 and fed via line 22 to motor control circuit 21, Which receives command signals from input 23.

Signals from diode 19 are evaluated in circuit 24 and form a first input to differential amplifier 25. The second input to amplifier 25 i...