Browse Prior Art Database

Track Following Servo System

IP.com Disclosure Number: IPCOM000093416D
Original Publication Date: 1967-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Cordano, RD: AUTHOR

Abstract

This servo system assures accurate positioning of a servo-controlled transducer 10 with respect to prerecorded servo or position tracks on a moving magnetic storage medium 11 with a simplified control network. The system includes a number of position tracks 12...15 recorded immediately adjacent each other. Each track is recorded with a ramp or sawtooth waveform so that it includes sharp magnetic transitions of the same polarity sufficient to effectively saturate the medium interleaved with gradual magnetic transitions of the opposite polarity. This type of recording provides a much larger flux change per unit of distance for the sharp transition than the gradual transitions.

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Track Following Servo System

This servo system assures accurate positioning of a servo-controlled transducer 10 with respect to prerecorded servo or position tracks on a moving magnetic storage medium 11 with a simplified control network. The system includes a number of position tracks 12...15 recorded immediately adjacent each other. Each track is recorded with a ramp or sawtooth waveform so that it includes sharp magnetic transitions of the same polarity sufficient to effectively saturate the medium interleaved with gradual magnetic transitions of the opposite polarity. This type of recording provides a much larger flux change per unit of distance for the sharp transition than the gradual transitions. When read by transducer 10, the sharp transitions develop periodic sharp voltage pulses of equal polarity while the gradual transitions produce no substantial signal.

The several position tracks are recorded so that the sharp transitions of the odd-numbered tracks are of opposite polarity from the sharp transitions of the even-numbered tracks. The tracks are also preferably offset so that the sharp transitions in one occur between the sharp transitions in the next.

Transducer 10 is positioned to read the position tracks as they pass beneath and is movable transversely of the tracks under control of actuator 16. Transducer 10 produces positive and negative voltage pulses, the amplitudes of which are functions of the position of transducer 10 over the tracks. The head data is amplified by AC differential amplifier 17. The positive and negative pulses are detected and held between sample...