| 摘要 |
PURPOSE:To attain uniformly-high demagnetizing effect with no need to replace any components, by memorizing a demagnetizing pattern having a plurality of switching cycles and by switching the polarity in a desired cycle by the slection of the demagnetizing pattern. CONSTITUTION:When an initial address is selected 22 and set by a signal for starting demagnetization and an initial-address signal is sent ti a memory 18, a convecting demagnetizating-pattern signal is called and the excitation polarity of a coil 16 is switched over L . A pulse is generated 26 and counted 24, and when it reaches a specific value specified by the memory 18, a riple carry is generated 24 and an address-changing signal is selected 28. By the address changing signal an address is set 20 and transmitted to the memory 18 and a selected demagnetizing pattern is made to operate in succession to the initial pattern, while the memory 18 sets another specific value. And, when the count 24 reaches this specific value, the ripple carry is emitted. By the repetition of this operation, the cycles of switching normal and reverse direct currents is reduced gradually with the time for excitation of the coil 16 between them, the setting 20 of the address is stopped by the completion of the demagnetizing pattern, and thereby the excitation of coil is stopped. |
