Low flying head detection using readback signal amplitude modulation

Abstract

A method for determining whether a data storage device read/write head is a low-flying read/write head or a non low-flying read/write head. A disc attached to a spindle motor is accelerated to an operating rotational velocity, the head is positioned over a portion of the disc non-accessible to customer data and a data pattern of selected frequency is written. A magnetoresistive element of the is biased and the data pattern is read while the disc is decelerated to a predetermined rotational velocity threshold. Occurrence of a read signal landing signature comprising readback signal amplitude modulation prior to reaching the predetermined rotational velocity threshold identifies the head as a low-flying head. Contrawise, non-occurrence of the read signal landing signature prior to reaching the predetermined rotational velocity threshold signifies the head as a non low-flying head.

1 . An apparatus for detecting low fly height performance of a transducer comprising a circuit configured for relating fly height to a readback signal amplitude modulation.