In a television reproduction system in which recorded video for one field, either odd or even, is repeatedly scanned, such as for still or slow motion reproduction, and is displayed with a locally generated synchronizing signal which produces interlaced scanning having both odd and even fields on a television...http://www.google.com.tw/patents/US4251830?utm_source=gb-gplus-share專利 US4251830 - System for removing vertical vibrations from reproduced video
