| 摘要 |
PURPOSE:To apply an erasing signal to a recording medium through a magnetic head and to simplify and miniaturize the circuit constitution of a magnetic eraser by reversing polarity synchronously with the detection of a relative position between a magnetic head and a recording medium and generating an erasing signal reducing the absolute value of amplitude. CONSTITUTION:The relative position between the magnetic head 1 and the magnetic tape 2 is detected by a position sensor 11 and an output from the sensor 11 is inputted to a switching signal generating circuit 10 and an erasing signal generating circuit 5. The polarity is reversed by a counter 510 and a data converter 511 in the circuit 5 synchronously with the detecting signal of the sensor 11 and a signal for reducing the absolute value of the amplitude is outputted. The output from the converter 511 is processed by a D/A converter 512 and an amplifier 513 and the processed signal is inputted to a change-over switch 9 together with an output generated from a recording signal generating circuit 6. Thus, AC signal can be erased by said simple circuit constitution, noise generation can be suppressed and the device can be miniaturized.
|
