| 摘要 |
<p>PURPOSE:To perform stable fast-forward and rewind control at constant tape speeds, by controlling a payoff and a take-up reel so that the sum of the square of their rotation periods is constant. CONSTITUTION:Signals having pulse widths corresponding to rotation periods TT and TS of the payoff and take-up reel turntables are sent from rotation period detectors 4 and 5 attached to the reel turntables respectively to F/V converting circuits 6 and 7, which outputs voltage signals VT and VS to square- law circuits 8 and 9 for square-law arithmetic. Their outputs V<2>T and V<2>S are added by an adder 10 to a specific value -A<2> from a reference voltage power source 11. Its output is sent through an LPF12 to a driving amplifier 14 or 15 by a changeover switch 13 according to fast-forward (FF) or rewind (REW) mode. Then, a take-up reel motor 16 or payoff reel motor 17 is driven by the output of said amplifier so that the output of the LPF12 is zero. Thus, the fast-forward and rewind control with constant tape speeds is carried out.</p> |
