Ground station digital interface

Digital computer interface equipment was developed to enable the recovery of digital data encoded in special format and recorded, both in flight and in laboratory experiments, using an analog magnetic tape transport. The recorded data were first reproduced, in a continuous manner, at a ground station processing center, using an analogue magnetic tape reproducing machine and was then taken to the input of the interface equipment. Serial to parallel conversion of the data into 16-bit words suitable for direct entry into a computer, under interrupt control, was performed by the interface equipment. Time-of-day information which is normaly multiplexed with other digital data and recorded on the magnetic tape, effectively constitutes an identifier which may be used for specifying the location of any areas of interest on the tape. To enable the analog reproducing machine to be stopped at any predetermined location, a present stop signal generator was incorporated in the interface equipment. Complete details, together with a functional description, of each circuit within the digital interface equipment are included.