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A Ground Loop Read Line Shield Using the Write Lines in a Disk File Recording Channel

IP.com Disclosure Number: IPCOM000037437D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Brede, DW: AUTHOR

Abstract

In a disk file the interconnection between the read element and the associated read circuitry is a source of noise in the read signal. Prior disk files have used a twisted pair of fine wires for this interconnection. Use of wire is expensive in material cost and in the labor required to make the assembly. Recent designs for this interconnection have employed various flat cable technologies. Where the recording scheme features separate write and read elements, the interconnection will have at least 6 lines, 2 for write, 2 for read and 2 for read shielding. The invention described herein consists of using the write leads for the read shield function, as shown in the figure. This is possible because the read and write functions are mutually exclusive.

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A Ground Loop Read Line Shield Using the Write Lines in a Disk File Recording Channel

In a disk file the interconnection between the read element and the associated read circuitry is a source of noise in the read signal. Prior disk files have used a twisted pair of fine wires for this interconnection. Use of wire is expensive in material cost and in the labor required to make the assembly. Recent designs for this interconnection have employed various flat cable technologies. Where the recording scheme features separate write and read elements, the interconnection will have at least 6 lines, 2 for write, 2 for read and 2 for read shielding. The invention described herein consists of using the write leads for the read shield function, as shown in the figure. This is possible because the read and write functions are mutually exclusive. To use the write leads as the read shield requires that the write leads enclose, i.e., lie on each side of, the read lead pair. This means that the read and write element terminal pads on the slider must be rearranged so that the write element pads enclose the read element pads. The circuit end of the interconnections leads also requires modification. In the circuit chip, the write driver output pads must enclose the read signal input pads. In addition, the write driver output must have a switching element on each output line to ground these lines when not writing. These grounds would be turned off when writing and turned on when read...