Apparatus for distinguishing between standard and non-standard video signals

摘要

A source (10) responsive to a composite video input signal (S1) provides line and burst frequency related timing signals (Fh, 4Fsc). A measuring circuit (20) responsive to the timing signals provices measuremt values which tend to repeat when the video input signal is of a given color television standard and tend to exhibit a pseudo-random distribution otherwise. A signal processor (30, 40) provides a "histogram" (i.e., a frequency distribution) of the measurements occurring withing a given time interval and provides an output signal identifying standard and non-standard video input signal based on the histogram (frequency distribution) of the measurements. IMAGE