| 摘要 |
<p>PURPOSE:To attain the phase synchronization of drums between plural VTRs, by performing such control that the odd number of pulses are dropped or added in a reference signal of drum servo. CONSTITUTION:When one pulse is dropped from (added to) a reference signal 7, an input 8a of a circuit 9 has the phase inverted, and a drum FF signal 6 is inverted also because a speed control signal 10 is so outputted that the phase of the drum FF signal 6 is synchronized with the phase of the signal 8a. For the purpose of discriminating the phase of a drum FF signal 11 of a VTR to be synchronized with the signal 6, they are latched in D type flip flops 12 and 13 by a clock signal 18. If phases of drums coincide with each other, an output 21 of an inverter 15 becomes high-level, and the phases of drums are not changed; and if they are inverted, the output 21 becomes low-level, and the passage of the reference signal 7 is inhibited during the low level to omit one-pulse components of the signal. As the result, the signal 8a is inverted in phase, and the drum FF signal 6 is inverted also and coincides with the drum FF signal 11 in phase.</p> |
