The analog height sensor conversion circuit of the above circuit is given below. It is also in the 1992 Electronics Experimenter magazine article.
Varactor diodes are our varicaps of today. This circuit for switching signals in an RF circuit was found...
This Hughes circuit is from 1968. Equivalent modern components can be used. The input impedance is...
This circuit digitally counts input pulses. The circuit from a November 1970 Radio Electronics uses...