R&D Report 1973-06 : Equipment for the transfer of digital video signals to paper tape C.K.P Clarke A digital computer can be used to simulate processing methods for the bit-rate reduction of digital television. To assess such methods, television signals must be converted to a form compatible with computer data-handling systems. This report describes equipment for transferring monochrome pulse-code modulation signals derived from a slide scanner to punched paper tape. One eight-bit word is extracted from the repeated signal during each picture period and is then punched as a single eight-element character on the tape. The equipment has been used to produce two paper tapes each containing an area of picture 256 picture elements wide and 256 lines high. The report includes a picture reconstituted from one of the tapes. Because the phase of the colour subcarrier at a point in the picture is the same only once every four picture periods, the equipment must be modified to take samples at this rate, if it is to be used with coded colour signals. More extensive modification would be needed if subcarrier-locked sampling were to be used.
