| 摘要 |
PURPOSE:To obtain the reproduced pictures of high quality which are free from beats by supplying a degaussing current containing an alternating current of an attenuated vibration waveform to a rotary magnetic head during its idle scanning period. CONSTITUTION:In a production circuit 36 a demagnetizing signal Se is produced in the first 4/5 period of each field period. This signal Se has a rise at each start point of each field period and then turned into an alternating signal having an attenuated vibration waveform that is set at 0 within the corresponding field period. Then these signal Se are supplied to switch circuits 15 and 25 and at the same time a control signal is supplied from a production circuit 50. Then addition signals Ka and Kb and signals Ra and Rb containing signals Se following the signals Ka and Kb are extracted out of circuits 15 and 25 respectively and supplied to rotary magnetic heads 1A and 1B. Thus both heads 1A and 1B are degaussed by the signals Se. Furthermore the periods of signals Se are out of a period when both heads have no scanning of a tape 2. This produces no trouble when the tape 2 is recorded.
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