Hewlett-Packard Company

Andrew David Brown

Christopher Huw Williams

Richard D Barndt

Robert Philip Morling

Simon John Chandler

A device is described for increasing the rate at which data may be written to a magnetic data storage medium. The device includes circuitry for amplifying the data and circuitry for writing the data to a data storage medium. The circuitry for amplifying the data includes: circuits for amplifying the data; delaying and amplifying the data; and adding the amplified data and the delayed and amplified data.

Double pulse write driver

A method is described of calibrating a write pre-equalization circuit in the write channel of a magnetic data storage device which maximizes the rate at which the write channel can write to a data storage medium. The method includes the steps of: setting an amplitude of a delayed current to a minimum value ; setting a delay period of the delayed current to a minimum value; setting an amplitude of a main driver current to a minimum value; recording a low frequency test signal to the data storage medium; reading the low frequency test signal from the data storage medium; monitoring a quality metric of the low frequency test signal; varying the amplitude of the main driver current over a range of amplitudes; selecting an optimum amplitude of the main driver current; setting the delay period of the delayed signal to a predetermined value; recording a pseudo-random test signal to the data storage medium; reading the pseudo-random test signal from the data storage medium; monitoring a quality metric of the read pseudo-random test signal; varying the amplitude of the delayed current over a range of amplitudes; and selecting an optimum value of the delayed current, depending on the monitored quality metric.

Calibrating write pre-equalization in a data storage device

An adaptive (FFE) filter 24 adaptively filters a signal and updates a plurality of coefficients stored on capacitors 69 to minimize the error between the filter output at 72 and a set of notional reference values supplied by a reference generator 74. The stored values of one or more coefficients are monitored and if the monitored coefficient or coefficients pass respective thresholds or leave respective ranges, indicating the onset of maladaption a default set of coefficients is forced.

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Bristol, United Kingdom

Andrew David Brown