Method and apparatus for testing characteristics of a floppy disc and a floppy disc drive
AssigneeBenares Limited
InventorsJames O'Reilly, Finbar Kavanagh
Life of this patent
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Abstract
Method and apparatus for determining the alignment of a data track on a magnetic disc, for example a floppy disc and for determining the alignment of a read/write head in disc drive writing apparatus. In the method the radius of the circumferential center line of the track is determined by determining the radius of the peak value of the transverse envelope of the signal on the data track. The peak value is determined by computing the track average amplitude at a number of incremental positions transversely across the data track. The peak value and its radial position is then computed using a parabolic curve fitting technique.
Claims18
A method for testing alignment of a data track written on a magnetic disc, the method comprising the steps of:
- rotating the disc,
- positioning a reading means at a first known radial position relative to the centre of the disc over the data track,
- reading the signal of the track over at least portion of the circumferential length of the track at the first known radial position, and determining the track average amplitude of the signal over the read circumferential length of the known radial position,
- moving the reading means respective incremental distances transverse of the track to second and subsequent known radial positions, relative to the centre of the disc,
- reading the signal of the track at each of the known radial positions and determining the track average amplitude of the signal at the said known radial positions,
- continuing to move the reading means incremental distances transverse of the track until the value of the track average amplitude of the signal obtained from a reading is less than the track average amplitude of the signal of the reading for the previous position,
- obtaining the radius of the centre line of the data track by determining the radial position of the peak value of the track average amplitude of the signal from the readings taken, and
- comparing the radius of the centre line of the data track with the radius at which the centre line of the data track of a correctly aligned data track would have occurred, to determine the track alignment.
Apparatus for testing alignment of a data track written on a magnetic disc, the apparatus comprising:
- means for rotating the disc,
- reading means for reading data from the disc,
- means for moving the reading means radially across the disc and for selectively positioning the reading means at a plurality of radially spaced apart positions on a data track,
- means for recording the radius of each position from the centre of the disc,
- means for determining the track average amplitude of the signal of the track at each position over at least a portion of the length of a track from which data is read by the reading means,
- means for obtaining the radius of the centre line of the data track by determining the radial position of the peak value of the track average amplitude of the signal from the values of the track average amplitude and their positions, and
- means for comparing the radius of the centre line of the data track with the radius at which the centre line should have occurred in a correctly aligned track.
Dependencies are inferred from the claim text.