Variable picture size underwater television camera - uses synchronous switching in line and frame coil circuits to vary picture size in discrete steps

摘要

The underwater television camera has horizontal and vertical scan circuits that can vary the scanned picture circuits on the picture tube whilst in operation. Horizontal scanning is varied by switching additional inductances in series with the line coil or by switching the tappings of the line output transformer. Vertical scanning is varied by switching additional resistors so as to vary the current of the frame coil circuit. The switching takes place in discrete steps by synchronous operation of the double pole electromagnetic relays to give discrete changes of picture size. Further, it is possible to vary the position of the picture surface by varying the d.c. current in the line and frame coils from a high impedance source simultaneously with the variation of picture size.