The testing and operation of 4¿in. image orthicon tubes

The methods used by a broadcasting organization to check the performance of image orthicon tubes are described. Aspects dealt with include: the transfer characteristic; sensitivity; contrast handling ability; signal/noise ratio; picture sharpness; geometrical distortion and linearity; microphony; uniformity of picture background; freedom from spurious effects; lag, movement blur, sticking, etc.; colour response; freedom from drift; ease of adjustment. Some conclusions are drawn on particular aspects of operating these tubes.