| 摘要 |
PURPOSE:To prevent a runaway of a reel by controlling a capstan servo circuit, by providing a means which detects the target value of the capstan speed servo circuit being within a specific range and a means which detects a tape speed exceeding a specific value. CONSTITUTION:The target speed of a capstan is set in a limiter 20 and phase compensation 21 is performed to drive a motor 23 at a specific speed through a driving amplifier 22. The speed of the motor 23 is F/V-converted 24 with pulses from the frequency generator FG of a timer roller 5 to perform capstan servocontrol. The output of the rate limiter 20 is supplied to a window comparator 30, which outputs a high-level signal when the target value of the capstan speed servo circuit is not within a specific low-speed range including a stop mode. The FG pulses from the timer roller 5 are supplied to a speed sensor 31, which outputs a high-level signal when the input is higher than a prescribed value. When both inputs are at high levels, a system controller 33 outputs a servo-off signal. Thus, a runaway of a reel is prevented. |
