EQUIPMENT AND METHOD OF DETECTING TAPE-EDGE BY USING MR NOISE

摘要

PURPOSE: To detect a medium edge by causing a processor to compare an off- tape noise voltage with an on-tape noise voltage, divide the comparison value by an integer greater than 1, and set a reference noise voltage for positioning an MR element with respect to an edge of a travelling magnetic tape. CONSTITUTION: A controller 44 suitable for actuating a voice coil control unit 65 in response to a signal from an MR element 46 is provided. On-tape noise voltage reading is detected by a differential amplifier 60 connected over a lead of the element 46. This amplifier 60 receives an on-tape noise voltage processed in the same manner as the off-tape noise voltage with respect to a processor 78. The processor 78 compares the off- and on-tape noise voltages, then divides the comparison value by an integer greater than 1, and sets a reference noise voltage for positioning the element 46 with respect to an edge 22E of a travelling magnetic tape.