SCAN LOSS DETECTOR

摘要

A display system includes a kinescope (20, fig. 3). A horizontal scan detector is coupled to a source of a horizontal scan current signal (40) and detects a loss of horizontal scanning. In addition, a vertical scan detector (52, 54) is coupled to a source of a vertical scan current signal including a feedback path (RS) and detects a loss of vertical scanning. A vertical feedback detector (Z1, R12, R13) is also coupled to the vertical scan current signal source, and detects a failure of the feedback path in the vertical scan current signal source. A controllable kinescope driver circuit (T4, fig. 3), coupled to the kinescope, the horizontal scan detector, the vertical scan detector and the vertical feedback detector, blanks the kinescope if the horizontal scan detector detects a loss of horizontal scanning, the vertical scan detector detects a loss of vertical scanning or the vertical feedback detector detects a failure of the feedback path.