The Transcribed Demonstration
J. Bourland, V. Burns, C. Sadler, T. Sartor, G. Cantrell, T. Coulter, Linda Geddes · IEEE Transactions on Communications · 1974
A new system of self-instruction which combines the desirable features of video tape and analog graphic recording is developed. By means of multiplexing techniques, four types of information are recorded on standard video tape: 1) video, 2) voice, 3) three channels of physiological data, and 4) control signals for the operation of auxiliary equipment. The latter three are combined and applied to a single audio track of the video tape recorder by successive time-division and frequency-division multiplexing; the video channel is unaltered.