Browse Prior Art Database

Magnetic Disc Edge Locator Resolution Enhancement Scheme

IP.com Disclosure Number: IPCOM000081573D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Jordan, FE: AUTHOR

Abstract

This resolution enhancement arrangement improves the accuracy of determining the position of the edges of spinning magnetic discs.

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Magnetic Disc Edge Locator Resolution Enhancement Scheme

This resolution enhancement arrangement improves the accuracy of determining the position of the edges of spinning magnetic discs.

The arrangement includes an electronic optical system using photodiodes. The electronic returns from a white edge target material 1 mil thick, produces signals averaging about 4 to 5 pulses for each disc edge. It is assumed that the light reflected electronic returns are directly proportional to the surface area presented by the target. For example, returns from a central portion of the disc yield a maximum amplitude, whereas returns from close to the edge are proportionally smaller depending on the closeness to the edge. The following formula is utilized in the arrangement: Resultant position from 0 = (return amplitude 1)(distance 1) +(return amplitude 2)(distance 2) +etc Over sum of all amplitudes. This method is similar to the technique used in mechanics for finding the resultant force by taking moments about a reference.

A typical example has the return pattern shown in Fig. 1. Fig. 2 shows a block diagram of the electronic implementation necessary to solve the above equation.

The level detectors 22 measure the amplitude of the video return signals reflected from the disc edges. These amplitude or level signals are multiplied by the return count position of the amplitude signal or distance. The product is counted and put into the read-only memory 24. The various returns are...