Found in a 1980s telecommunications documentation, the circuit presented acts as a product detector. The modulator or mixer in the square may be that of the previous circuit.
This circuit is used in transceivers, enabling input selection by diode switching through polarity...
This configuration was found in an American publication from the 90s. Operators admit equivalents just...
This circuit was found in an Italian magazine Elettronica Prática of 1977. The transistors can be...