| 摘要 |
<p>PURPOSE:To enable reproduction of TV signals of any method, by discriminating the recording method by the frequency or period of control signal detected from the recording medium, and supplying bias voltage corresponding to the discriminated method into a drum servo circuit. CONSTITUTION:When a magnetic tape 3 runs according to the control of a capstan servo circuit, a control signal 37 is detected by a control head 12b, which becomes an output signal 67a to enter a counter circuit 69, so that the pulses are counted according to gate pulses 70a of pulse generator 70. As a result, the frequency of the signal 37 is discriminated, and an output signal 69a of the circuit 69 turns off a switch 71a. At this time, the voltage of power source Vcc is voltage divided by resistances R4 to R6, and is supplied into terminal Y of discriminator-amplifier 51 as the bias voltage corresponding to the recording method. The terminal Y is also supplied with outputs from driving amplifier 52 and phase detector 66, so that a feedback loop is composed. Thus, TV signals of any method may be reproduced.</p> |
