Phase locking system for television signals using a digital memory technique

摘要

A phase locking system locks at least one incoming composite video signal to the synchronizing signals of a second, reference wave. The incoming signal is strobed at a rate dependent upon the incoming color subcarrier into a memory, essentially on a field-by-field basis. Circuitry is provided by grouping the fields on a repeating field-tagged basis (groups of four for the NTSC signal format) to maintain signal integrity.