Telecine film weave correction

摘要

Horizontal position values are produced from horizontal error signals and picture start pulses from vertical error signals. The picture start pulses are only released during part of the picture scanning period and are blocked during the remainder of the period. The blocking and release part of each picture scanning period is determined by a tacho unit in slip-free engagement with the perforation of the film, and in which when there are no picture start pulses during the release part, switching automatically takes place to replacement pulses derived from the unit.$ Window pulses are derived from the pulse signal of the unit and picture start pulses, and second window pulses are derived from the pulse signal of the unit. The release part of each scanning period is formed by the first window pulse and than when there are no picture start pulses during the release part, the replacement pulses are produced with the aid of the second window pulses.$