Auto balancing duplexer for communication lines

摘要

A circuit for generating a control signal for use in a communication line duplexer or other isolation means. The transmitted signal at the output of the duplexer is phase detected to detect its real and imaginary components. These components are used to modulate the transmitted signal which is then injected into a feedback loop of the duplexer. This substantially cancels the transmitted signal at the output of the duplexer. The circuit permits the communication line to be terminated in a constant impedance.