| 摘要 |
<p>PURPOSE:To obtain always a stable control signal, by detecting a peak value of a reproducing control signal and using its voltage as a DC shift voltage to control the setting of a comparison level. CONSTITUTION:A peak-to-peak value of the reproducing control signal from a magnetic tape 1 is detected by a peak detector 4, and a DC voltage corresponding to the peak-to-peak value of the reproducing control signal is generated through a differential amplifier 5 and becomes a DC shift voltage. This shift voltage is superposed onto the reproducing control signal by an adder 6 and is processed in a comparing circuit 7, where a reference voltage is set, to generate a servo control signal. By this system where the setting of a comparison level is controlled by the DC shift voltage corresponding to the peak value of the reproducing control signal, the servo control signal corresponding only to a correct reproducing control signal is generated even if the control signal has a level difference and noise or the like is mixed, and thus, a reproducing device where malfunctions are prevented is obtained.</p> |
