TV device for control of vertical pulse frequency and phase - provides automatic control by comparison with external AC voltage via time constant measuring RC element

摘要

The television system has automatic control to adjust the vertical pulse frequency to a predetermined alternating voltage frequency and to adjust the phase relation between these signals. Frequency and phase comparators are included. A long time constant RC element (10, 11) is controlled by the output signal from the comparator (1). An oscillator (13) is voltage controlled and gives a defined multiple frequency of the vertical signal. The comparator (1) changes the capacity (11) value of the RC element (10, 11), when there is a difference in frequency and phase greater than a predetermined value. A store (28) has its two outputs (a, b) connected via diodes (8, 9) to the RC element. The logic state of the signals changes the capacity value of the RC element.