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Floppy Disk Signal Modulation

IP.com Disclosure Number: IPCOM000061803D
Original Publication Date: 1986-Sep-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Geist, T: AUTHOR [+2]

Abstract

The percent variation in signal strength, or modulation, which is experienced about the circumference of a chromium dioxide floppy magnetic recording disk is minimized by controlling the disk's particle loading. Ideally, such magnetic recording disks are unoriented, that is, an unrecorded disk displays no preferential magnetic field in any direction in the plane of the disk. Such a disk is said to have an orientation ratio of 1.0 (where orientation ratio is defined as the squareness ratio measured in the direction of head movement, divided by the squareness ratio at an angle 90Πto this movement). Since the modulation is a function of the orientation ratio, the variation in signal strength around a recorded floppy disk approaches zero as the orientation ratio approaches a value of 1.0.

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Floppy Disk Signal Modulation

The percent variation in signal strength, or modulation, which is experienced about the circumference of a chromium dioxide floppy magnetic recording disk is minimized by controlling the disk's particle loading. Ideally, such magnetic recording disks are unoriented, that is, an unrecorded disk displays no preferential magnetic field in any direction in the plane of the disk. Such a disk is said to have an orientation ratio of 1.0 (where orientation ratio is defined as the squareness ratio measured in the direction of head movement, divided by the squareness ratio at an angle 90OE to this movement). Since the modulation is a function of the orientation ratio, the variation in signal strength around a recorded floppy disk approaches zero as the orientation ratio approaches a value of 1.0. For any given formulation of magnetic recording, a critical loading of chromium dioxide magnetic particle produces adequate signal strength from the resulting media, and also produces an orientation ratio of 1.0. Pigment volume concentrations in the range of 49.3 to 52.3 are exemplary of those which yield an orientation ratio of 1.0.

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