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Browse Prior Art Database

Total Surface Magnetic Tape Test

IP.com Disclosure Number: IPCOM000076294D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Barth, HV: AUTHOR

Abstract

Total surface testing of tape is accomplished as shown, by butting the test tracks and testing for defects in each track as well as between tracks. The magnetic read and write heads are butted together so that spacing between tracks is very nearly zero (0.002 to 0.004 inch).

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Total Surface Magnetic Tape Test

Total surface testing of tape is accomplished as shown, by butting the test tracks and testing for defects in each track as well as between tracks. The magnetic read and write heads are butted together so that spacing between tracks is very nearly zero (0.002 to 0.004 inch).

With close spacing of heads and tracks, there will be crosstalk between the read heads. However, for total surface testing, crosstalk can be tolerated because the recorded signals are recorded in phase.

To detect a defect, the amplitude of the signal from each track is monitored with a high-threshold detector 10. To detect defects between tracks, the signal from each track is monitored with a low-threshold detector 12, and the output of the low-threshold detectors for adjacent tracks are ANDed together. Thus, if the less sensitive threshold is satisfied by two adjacent tracks, the appropriate AND circuit 14 will have an output indicating a defect between the tracks.

In operation, tape 16 is recorded with parallel AC signals by butted heads 18. Butted heads 20 then read the inphase signals, amplify the signals in amplifiers 22, and pass the signals to the threshold detectors 10 and 12 for each track. Output from one of the threshold detectors 10 indicating a defect in a track is shown as TK-3 defect, TK-4 defect, or TK-5 defect in the drawing. Defects between tracks are detected by the output of the low-threshold detectors 12 being ANDed by AND gates 14. The ou...