This voice scrambler and descrambler circuit was found in a Radio Electronics from July 1963. Transformers are common types at the time with impedances according to telephones and line.
This circuit can be used in bridge of sensitive measures. We found it in a documentation from the...
This interface was found in a Modern Electronics magazine from 1990. Although the circuit is...
Found in an old American documentation, this step has as input and output transformers coupling. Two...