Transfer Characteristics and Spectral Response of Television Camera Tubes

Abstract

It is the intention of this chapter to describe methods of presenting television camera tube characteristics that will cover all camera tubes regardless of their spectral sensitivity. Although the majority of present-day camera tubes are sensitive only in the near-ultraviolet, the visible, and the near-infrared spectrum, it is felt that a general method of presenting television camera tube characteristics that can be used for any spectral region will be more useful than a method that is applicable only to the visible spectrum. The major application for television camera tubes has been, and probably still is, the entertainment field. The need for precise definition of the tube characteristic does not exist for the entertainment field or a few similar applications. Consequently, a certain amount of subjectivity has been evident in the stating of television camera tube characteristics. However, television camera tubes are now being used more and more for scientific, engineering, and defense applications, where the need exists for objective and relatively accurate means of stating the tube characteristics. For this reason, the more general radiometric units for input signal are preferred over the more common photometric units. Measurements will be given in radiometric units, and I shall show how to transfer from either set of units to the other. The output signal will be given both in terms of signal current and in signal-to-noise ratio.