| 摘要 |
<p>PURPOSE:To obtain a brake stability the same as one in case of a treble mode even in a throw at a standard mode of a device such as a VTR by providing a means which detects the number of revolution of a motor for driving a tape and applies a fixed quantity of a brake after the running speed is made constant. CONSTITUTION:An FG output generated by a magnetic FG, etc. is waveform- shaped by an FG amplifier 23 and a Schmitt circuit 45, frequency detecting voltage (f) is obtained by a Schmitt circuit 47 using conversion voltage (e) acquired through an F-V converter 46 as an input, and fixed brakes are applied from the point and a capstan motor (not shown) is stopped. That is, speed detecting set speed F2 (b) is detected by the F-V converter 46 and the Schmitt circuit 47 for a brake period T3, a monostable multivibrator circuit 48 for finely adjusting brake width is triggered by a rise of frequency detecting voltage (f), and an FF 49 for determining the direction of rotation is reset (h) by an output (g) from the circuit 48.</p> |
