| 摘要 |
<p>PURPOSE:To prevent an unnecessary signal output by providing a gain reducing circuit, which is operated when a gate circuit is turned off, in a circuit to amplify the output of the gate circuit, which is controlled by a gate signal, when the gate circuit is turned on. CONSTITUTION:A control signal to be read from a magnetic head 2 is amplified by a gate circuit operational amplifier 5. The output is supplied through a comparator 6 to a timing generating circuit 7 and a gate circuit 4 is turned on and off by the control signal from the circuit 7. The control signal from this circuit 7 is also supplied through an inverter 9 to a switch 8 of the gain reducing circuit. When the circuit 4 is turned off, the switch 8 is turned on and the gain reducing circuit goes to an operating condition. Thus, the level of a noise, etc., is lowered during an unnecessary period and malfunction is prevented from being generated.</p> |
