ADAPTIVE ELECTRONIC HYBRID CIRCUIT

摘要

An electronic hybrid circuit for matching a two wire telephone circuit to a four wire telephone circuit is described. In one embodiment, the circuit includes a variable impedance circuit one end of which is driven by a reception signal on the four wire side and the other end of which is connected to a terminal of the two wire circuit. The impedance of the variable impedance circuit varies according to the characteristics of the two wire circuit. The hybrid circuit also includes an adder which adds in reverse reverse phase a half value of the reception signal on the four wire side to a signal from the two wire side, the resultant signal being a transmission signal on the four wire side. According to the invention matching is achieved regardless of variable factors such as length of two wire circuit and terminal impedance at its other end.