This dual balanced modulator configuration was obtained in a 1980s telecommunications documentation. The circuit makes use of transformers and the diodes are commonly used.
From an article in Radio Electronics magazine, May 1989, this circuit requires a dual power...
We found this circuit in a 1967 Electronic design. However, it can be easily implemented even...
Old phones with dials can be used in a simple home intercom system, as this circuit from Popular...