Using a sensor from the time, this circuit was found in the 1992 Radio Electronics Handbook magazine. The circuit uses a pair of integrated two-digit A/D converters.
This sophisticated function generator circuit appeared in the September 1972 issue of Radio...
We found this circuit in a 1975 publication. The circuit can be made with more modern equivalent...
The open output voltage on this circuit is approximately three times the peak value of the input...