| 摘要 |
<p>PURPOSE:To avoid a case where the fluctuation of the tape speed causes a malfunction by monitoring directly the duty of a reproduction control signal through a high-speed microcomputer and by executing the monitoring with a microcomputer. CONSTITUTION:The functions of a duty discriminating means 2 and a cycle discriminating means 3 are attained by a program searching CPU10. The duty of a reproduction control signal can be measured directly through retrieval of program searching by means of a microcomputer since the CPU has a high- speed operation. In this case, the clock cycle is set at 1mus and the level is monitored every 20mus in the duty measurement mode of the reproduction control signal. No problem is produced even in case the cycle of the normal control signal is set at 25Hz or 30Hz since the duty of the control signal is measured directly. A countermeasure is also possible to the fluctuation of the tape speed since the level is checked at a high speed. Furthermore the tape speed is slowed down automatically with discrimination of the control cycle even in case the tape speed is increased too much. This produces no malfunction of retrieval.</p> |
