Use of unbiased MR sensors in a rigid disk file

Unbiased magnetoresistive heads for magnetic recording have been fabricated and shown to operate at better than 10/sup -8/ byte error rate with a modified peak detection channel at low linear density to prevent intersymbol interference. The heads produce unipolar signals from their quadratic transfer curves. Theoretical comparison of the unbiased and biased designs shows that (1) intersymbol interference reduces the unbiased sensor amplitude more than that of the biased sensor, but produces the same amount of peak shift in both, (2) linear equalization cannot remove intersymbol interference for the unbiased head, (3) the unbiased head signal has higher bandwidth because it both doubles the fundamental frequency and has sharper peaks, (4) the unbiased head has improved tolerance to amplitude errors and similar tolerance to peak shift errors caused by crosstalk from adjacent tracks, and (5) the total disk moment to total sensor moment must be three times greater for the unbiased head to have the same amplitude as the biased head for a given read gap dimension.<
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