Electronic circuit to reduce noise in digital subscriber loop and communications over unsheilded twisted pair metallic conductors

摘要

In order to reduce noise in telecommunications made over unshielded twisted pair (UTP) of metallic conductors an active electronic circuit for a two-to-four wire hybrid circuit reduces common mode signals without recourse to inductive components. The hybrid has a balance network that dynamically alters its impedance to closely balance with the two wire line impedance. Residual common mode signals are cancelled. Resistors are connected to the wires and the circuit generates a high impedance to differential mode signals and a virtual ground to common mode signals.