TELECOMMUNICATIONS DEVICE COMPRISING AN EBD CIRCUIT, A TUNABLE IMPEDANCE NETWORK AND A METHOD FOR TUNING A TUNABLE IMPEDANCE NETWORK

A system having a tunable impedance network and a method of tuning a tunable impedance network are disclosed. In one aspect, a telecommunications device comprises an electrical-balance duplexer (EBD) circuit coupled to at least one output node of a transmit path (TXin), an antenna, and at least one input node of a receive path (RXout), wherein the EBD circuit is configured to isolate the transmit path from the receive path by signal cancellation, and a balancing network (Zbal) as part of the EBD circuit. In one embodiment, the balancing network is an integrated tunable impedance network configured to provide an impedance that matches a target impedance (Zant) associated with the antenna at a first frequency and simultaneously at a second, different frequency. The network comprises a first portion and a second portion, the first portion reducing the influence of the tuning of the second portion at the first frequency. In some embodiments, the network preferably comprises no explicit resistors.