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Driving Multielement Magnetic Head Arrays

IP.com Disclosure Number: IPCOM000086350D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Nystrom, W: AUTHOR

Abstract

In a typical multielement array head the mutual inductance between elements is the most significant path of crosstalk. If the circuit loop impedance for an element is Z and its mutual inductance with another element is M, the coupling factor is to a good approximation OmegaM/Z provided OmegaM<

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Driving Multielement Magnetic Head Arrays

In a typical multielement array head the mutual inductance between elements is the most significant path of crosstalk. If the circuit loop impedance for an element is Z and its mutual inductance with another element is M, the coupling factor is to a good approximation OmegaM/Z provided OmegaM<<Z.

Due to its nonlinear nature, a write driver has a much higher impedance in its steady-state condition, i.e., while fully conducting, than during switching. Consequently, it is much more sensitive to crosstalk during switching than during steady-state conditions.

By staggering the operation of the write drivers with respect to time, so that no adjacent elements are ever switched simultaneously, crosstalk is substantially reduced. The principle can be extended further so as to include next to nearest neighbors, and so on.

In microprogrammed systems, this can be done without any additional circuitry, since the interval between clock pulses has been subdivided already.

If a read while write scheme is being used, this method of staggered operation will also reduce the write-to-read crosstalk or feedthrough. The worst case feedthrough occurs when all write elements switch in phase simultaneously. The time staggering will prevent this from happening.

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