Inventors:
Donald E. Shafer - Littleton CO
Assignee:
Honeywell Inc. - Minneapolis MN
International Classification:
H04N 588
H04N 584
H01J 2998
Abstract:
In a twin tube recording CRT system, apparatus is provided for accurately aligning the line scan trace of the two tubes with respect to each other. The positioning voltage applied to the vertical deflection plates of the two tubes is compared in a comparator network. When a substantial identity of the compared signals is detected by the comparator network, suitable indicating device, such as LED's, are actuated to indicate the proper alignment, without the need for visual reference to the face of the tubes. There is also provided an interrelated skew correction circuit for the two tubes wherein a sample-and-hold circuit samples the skew correction signal for the first tube at a selected point in the sweep thereof. That sampled signal is superimposed on the skew correction signal for the second tube, to effect an offset of that skew correction signal by the amount of the sampled signal of the first tube skew correction signal. That offset produces an effective continuation of the skew correction signal across the face of the two tubes.