CIRCUITRY FOR LINE RECOGNITION OF A TELEVISION SIGNAL

摘要

CIRCUITRY FOR LINE RECOGNITION OF A TELEVISION SIGNAL Circuitry for line recognition of a television signal comprises a serration detector which receives the sync pulse and separates the portion of the serration of the vertical sync pulse; a first counter which is coupled to the serration detector and produces output pulse at specific time interval between two successive output pulses of the serration detector; a circuit which is triggered by the output pulse of the first counter and produces a pulse; a second counter which receives said pulse and the horizontal retrace pulse, counts said horizontal retrace pulse when said pulse has a specific level, becomes quiescent when said pulse has another specific level, and then produces the line identification pulse on the desired horizontal line; a first decoder which is connected to said second counter and produces the reset pulse for resetting said first counter after said first counter completes its desired counting action; and a second decorder which produces the reset pulse for resetting said circuit after said second counter produces desired line identification pulse. -O - O