| 摘要 |
PURPOSE:To simply detect the disconnection of a head and the abnormality of a driver and to always monitor the operation of a writing circuit by combining changes in voltages applies to both the terminals of two heads to operate flip flop (FF) circuits and logic-circuits. CONSTITUTION:A 1st abnormality detecting means DA is constituted of an FF circuit, A NAND circuit, etc., and when the disconnection of the head is generated, detects the prescribed shift of phases between a waveform outputted from one track and that outputted from the other in the FF circuit to detect a head abnormality signal. A 2nd abnormality detecting means DB for detecting the abnormality of the driver is constituted of an FF circuit, a NOR circuit, etc., and when abnormality such as the disconnection of the driver is generated, outputs a driver abnormality signal. These abnormal signals are sent to the succeeding stage by an abnormality detection output means DC as abnormal signals. The terminal voltages on both the ends of the heads are always monitored by combining two tracks. Consequently, the disconnection of the writing head and the abnormality of the driver can be easily detected.
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