Method and apparatus for process control, tension control, and testing of magnetic media
AssigneeWashington University
InventorsRonald S. Indeck, Marcel W. Muller
Life of this patent
Estimating the term…
Abstract
A method and apparatus is disclosed for using the remanent noise of a magnetic medium as a fingerprint for benchmark testing of the magnetic medium as it is both manufactured and used. A cross-correlation is made between the fingerprint at various times as the magnetic medium is manipulated and is indicative of the integrity thereof. This cross-correlation media may be used to control manufacturing and recording processes, including tape tensioning and channel equalization. This cross-correlation between fingerprints can be used to control the tension applied to a thin film magnetic medium during record and/or playback.
Claims14
In a device having a head for at least reading data magnetically encoded on a magnetic medium, said device having means for controlling the tension of said magnetic medium as it passes by said head, the improvement comprising means for cross-correlating a magnetic fingerprint of said magnetic medium and controlling said tension control means in response thereto.
A method for controlling the tension of a magnetic medium as magnetically encoded data is at least read therefrom by a head, the method comprising the steps of:
- cross-correlating a magnetic fingerprint of said magnetic medium, and
- controlling the tension of said magnetic medium in response thereto.
A method for detecting a variation in a magnetic medium as said magnetic medium is manipulated, said method comprising the steps of:
- determining a magnetic fingerprint of a portion of said magnetic medium,
- determining again, after passage of time, a magnetic fingerprint of the same portion of said magnetic medium, and
- cross-correlating said two magnetic fingerprints to ascertain any differences therebetween, said differences being indicative of a variation over time in said magnetic medium.
Dependencies are inferred from the claim text.