Television reference signal digital indentification system

摘要

An electronic system for identifying a particular line of a plurality of lines in a pulse field, where, for example, the pulse field is either of the 262.5-line composite sync pulse trains produced by a conventional television receiver and the particular line is line 19 designated to carry a Vertical Interval Reference (VIR) signal, comprises digital circuitries for identifying a particular region corresponding to a known line in the pulse field and for counting from the known line to the particular line. Sensing circuitry determines whether a particular information component such as the VIR signal is present in each pulse field, and digital circuitry generates a presence indication signal when a presence indication criterion is met for the particular information component in a given plurality of fields.