| 摘要 |
1,085,695. Automatic speed control. AMPEX CORPORATION. July 20, 1966 [July 21, 1965], No.32642/66. Heading G3R. In a tape recorder, a low gain servoloop is used during the recording mode, and a high gain loop during playback. During a recording operation, the speed of motor 20, which drives tape 12 through capstan 18, is regulated in accordance with signals derived from standard frequency source 28 and encoder disc 22 respectively. The signals are compared in digital unit 26, the error signal being applied to the motor through carrier suppressor circuit 30 and low frequency filter and compensation circuits 32, 34 respectively. At the same time, a control track 42 of pulses from the source 28 is recorded on the tape at the full frequency or at a derivative of the full frequency of the source. During playback the control track 42 acts as the source of tachometer signals, and the gain of the servosystem is increased by replacing the units 32, 34 by similar units 32<SP>1</SP>, 34<SP>1</SP> adapted for high frequency, together with an amplifier 38. In another arrangement, the gain increase is accomplished by reducing the inertia of flywheel 23. |
