Subjective Rating of Visible Aliasing in Color Television Tubes and Comparison with a Theoretical Model

摘要

In color television tubes, the selecting device for the component colors acts as a sampling device of the signal that may result in a beat between the periodicity of the selecting device and the signal. For example, in shadow mask technology the selecting device is the mask itself. This beat limits the bandwidth of the signal that can be correctly reproduced and this limit cannot be evaluated by a straighghrward application of the sam- pling theory because of involved nonlinear factors and subjective aspects that must be considered. An experimental exploration concerning subjec- tive judgement of the visibility of aliasing was peformed. The results were compared with a theoretical model developed to predict the visual impact of aliasing during the design phase. The comparison seems to be satisfy- ing at the level of accuracy available. It was conformed that many ele- ments constituting the display system should be considered lf the aliasing artifact has to be reduced. The aliasing can be predicted and kept as low as possible by a comprehensive design of the shadow mask, the gun char- acteristics, and the video amplifier bandwidth, depending on viewing dis- tance, supported video standard and cost considerations, etc.'