Optimum Flying Erase Head Structure and Drive Conditions for Hi-Vision VTR Systems

Abstract

A flying erase head structure has been optimized to achieve sufficient erasability for Hi-Vision VTR systems with high coercive (> 1,500 Oe) metal particle magnetic tapes. Preferable erase head drive conditions have also been determined from erasability dependence on erase current amplitude and head core arrangements to the magnetic tape running directions with a 21.4m1s relative velocity. It was found that the most superior· erasability over -30dB is obtained with 45mA erase current at 20MHz erase frequency in the MIG head with Sendust films on both sides of the head gap edges, which is assured by 2-dimensional numerical analysis.lt has also been clarified that the erase head field transition width and the number of the erase head field reversals in the transition width are important factors for determining the erasability in the high frequency recording.