Model 10A79-4 Peak/Track/Hold Card
This extremely useful four-channel card can be remotely controlled to provide real-time capture of analog-signal peak values, both positive and negative (up to four inputs) that are pre-conditioned by other “A” cards within the same “A” rack on a System 10 mainframe.
The Model 10A79-4 will detect and store in analog (capacitor) memory the most positive and most negative values experienced by a given analog input signal since the input channel in question was last reset by an appropriate logic "TRACK" command. Each peak value will remain in memory until reapplication of the respective "TRACK" command, or until occurrence of a subsequent more positive or more negative signal excursion (thus permitting the capture of successively higher maxima or successively lower minima).
Since they are stored in on-board capacitor memory, captured peak values are subject to slow analog decay. However, you can easily arrange for any and all positive or negative peaks reported by a 10A79-4 channel to be indefinitely (digitally) held, without decay, by entering a CALCULATE (CLC) command of the form CLC x = MAX CHN y or CLC x = MIN CHN y .