This circuit was found in a 1968 EEE. The circuit makes use of logic gates of the time and can be tested with equivalents from modern families.
This circuit is from 2001 documentation, serving to multiplex stereo signals for FM transmitters. The...
This circuit reverses the signal if both positive and negative. We found it in an American...
Found in a publication by Gernsback from 1960, this circuit makes use of germanium transistors of the time....