A precision synchronizing system for large-screen television equipment

摘要

High-grade television receiving equipments, such as will be needed in large-screen installations, require a considerably more satisfactory synchronizing system than is provided in commercially-manufactured home receivers. A description is given of a complete circuit system of original conception, developed for incorporation into an experimental cinema equipment. It provides, under precise local control, line- and frame-trigger and black-level-clamp switching-pulse waveforms, all of which are derived from an advanced form of automatic phase follower and thereby rendered substantially immune from received interference and all but the most severe degradation of the signal. A significant technical advance is the introduction of automatic interlace, with fine manual control of interframe spacing to allow the removal of interlace error. Since the method adopted is tantamount to regeneration of the synchronizing signal, it would appear to be adaptable to other problems, particularly in network repeater stations.