| 摘要 |
Cyclic instrument control and data acquisition functions which are critically dependent upon synchrony are directed from a computer based system including a FIFO buffer adapted to feedback the most recently active word from its output register and re-store said word at a corresponding sequential position in the FIFO queue. To accommodate complex and interleaved control and data acquisition cycles, each FIFO word has a state portion for commanding external devices, a persistence portion for specifying the duration of a selected state active in the FIFO output buffer for a desired persistence interval, and a repetition portion for specifying the number of consecutive discrete repetitions of the currently active state-persistence datum at the output of the FIFO. Termination of the repetitions of the cyclic sequence is accomplished at the expiration of a preselected number of complete cycles. The FIFO input address is selected automatically in accord with the number of words comprising a single complete sequence of instrument control/data acquisition functions.
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