This paper describes the result of a study done under field conditions as to the measure and perceptibility of composite triple beat. Two interesting conclusions are drawn: (1) the threshold of perceptibility under field conditions particularly with regard to Pay Television signals and their contents occurs at a ratio of 57 db carrier to composite triple beat; (2) measurements of the composite triple beat near system generated thermal noise, such as those conducted on the trunk lines, require special consideration and techniques to insure their accuracy.