| 摘要 |
PURPOSE:To reduce the discriminating time and to improve the accuracy of discrimination by using a head switching signal and a defect detecting signal so as to discriminate a magnetic head to be defective if a defective reproduced output is detected in one magnetic head twice or over consecutively. CONSTITUTION:If a reproduction defective magnetic head takes place in a channel CH1, the reproduced output level corresponding to the channel CH1 is lowered. A DOC pulse as a detect detection signal is formed based on an output of a head amplifier and which channel of magnetic head causes the reproduction output defect is detected by using a head switching signal and the DOC pulse. It is possible by using the DOC pulse to check whether a period of the reproduction output defective magnetic head is at a 'High' or a 'Low' corresponding to the channel. Thus, if the reproduction output defect is detected twice or over consecutively for the magnetic head output period in one channel, the magnetic head is discriminated to be defective. Thus, the discriminating time is reduced and the accuracy of discrimination is improved. |
