Apparatus for analyzing the interface between a recording disk and a read-write head
AssigneeInternational Business Machines Corporation
InventorsCelia E. Yeack-Scranton, Siegfried F. Vogel
Life of this patent
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Abstract
A read-write head is provided with a plurality of piezoelectric transducers which produce signals related to its movement as it flies over an adjacently rotating recording disk. By filtering these signals to determine their spectral components in low, medium and high ranges, hard contacts between the head and disk, disk wear or roughness and head movement can be determined.
Claims15
An improved apparatus for testing a recording disk for determining its quality, said apparatus comprising:
- means for rotating such a disk;
- means for simulating the geometry, weight and material properties of a read-write head;
- means for moving said means for simulating to preselected positions across the surface of a recording disk while the disk is rotating on said means for rotating, whereby said means for simulating is spaced from the surface of the disk at a specified fly height due to rotation of the disk;
- at least one piezoelectric transducer means, mounted on said means for simulating, for producing first signals in response to acceleration or flexure or both by said means for simulating, due to movement of said means for simulating relative to or contact thereof with the rotating disk, or both;
- and
- means connected to said transducer means for selectively filtering said first signals to produce:
- second signals in a first frequency range in which spectral components of said first signals are indicative of rigid body accelerations of said means for simulating;
- third signals in a second, usually higher frequency range in which spectral components of said first signals are indicative of contacts between the disk and the means for simulating;
- and
- fourth signals in a third frequency range between said first and second ranges, in which RMS spectral components of said first signals are indicative of the roughness of flight of said means for simulating over the surface of the disk,
- where the frequency ranges are determined by the geometry of particular slider/transducer assembly chosen.
An improved apparatus for analyzing the interface between a recording disk and a read-write head in a recording system, comprising:
- transducer means for transforming mechanical movement of the head into representative electrical signals;
- and
- means for separating said signals into first and second spectral components representative of rigid body accelerations of the head and the roughness of the movement of the head over the surface of the disk.
An improved accelerometer for use in testing a recording disk to determine its quality, comprising:
- means for simulating the geometry, weight and material properties of a read-write head;
- at least one piezoelectric transducer means, mounted on said means for simulating, for producing signals in response to acceleration or flexure or both by said means for simulating, due to movement of said means for simulating relative to, or contact thereof with an associated recording disk, or both;
- and
- means for separating said signals into first and second spectral components representative of rigid body accelerations of the head and the roughness of the movement of the head over the surface of the disk.
An improved apparatus for analyzing the head-to-disk interface in a recording system, comprising:
- transducer means for transforming mechanical movements of the head into representative electrical signals;
- means for digitally capturing and preserving said electrical signals;
- and
- means for separating said signals into a plurality of spectral components representative of different physical characteristics of said movements.
Dependencies are inferred from the claim text.