An electrical balance duplexer has multiple impedance gradients and multiple impedance tuners. The electrical balance duplexer transmits an outgoing signal from a transmitter during a transmission mode when a first set of impedance gradients of the multiple impedance gradients is operating in a first impedance state and a first set of impedance tuners of the multiple impedance tuners is operating in a second state. The electrical balance duplexer isolates the outgoing signal from a receiver during the transmission mode when a second set of impedance gradients of the multiple impedance gradients and a second set of impedance tuners of the multiple impedance tuners are operating in the second impedance state.

An electrical balance duplexer has multiple impedance gradients and multiple impedance tuners. The electrical balance duplexer transmits an outgoing signal from a transmitter during a transmission mode when a first set of impedance gradients of the multiple impedance gradients is operating in a first impedance state and a first set of impedance tuners of the multiple impedance tuners is operating in a second state. The electrical balance duplexer isolates the outgoing signal from a receiver during the transmission mode when a second set of impedance gradients of the multiple impedance gradients and a second set of impedance tuners of the multiple impedance tuners are operating in the second impedance state.

An electrical balance duplexer has multiple impedance gradients and multiple impedance tuners. The electrical balance duplexer transmits an outgoing signal from a transmitter during a transmission mode when a first set of impedance gradients of the multiple impedance gradients is operating in a first impedance state and a first set of impedance tuners of the multiple impedance tuners is operating in a second state. The electrical balance duplexer isolates the outgoing signal from a receiver during the transmission mode when a second set of impedance gradients of the multiple impedance gradients and a second set of impedance tuners of the multiple impedance tuners are operating in the second impedance state.

An electrical balance duplexer has multiple impedance gradients and multiple impedance tuners. The electrical balance duplexer transmits an outgoing signal from a transmitter during a transmission mode when a first set of impedance gradients of the multiple impedance gradients is operating in a first impedance state and a first set of impedance tuners of the multiple impedance tuners is operating in a second state. The electrical balance duplexer isolates the outgoing signal from a receiver during the transmission mode when a second set of impedance gradients of the multiple impedance gradients and a second set of impedance tuners of the multiple impedance tuners are operating in the second impedance state.

A filter is provided that includes a set of cascaded resonator stages coupled between a filter input and a first filter output, wherein the filter includes a second filter output coupled to an output of a first or an intermediate one of the set of cascaded resonator stages. Another filter includes a set of cascaded resonator stages coupled between a first filter input and a filter output, wherein the filter includes a second filter input coupled to an input of an intermediate or a last one of the set of cascaded resonator stages. Both filters are configured to apply a first filter frequency response to a first signal propagating via the set of cascaded resonator stages, and apply a second filter frequency response to a second signal propagating via a subset of one or more of the set of cascaded resonator stages.

An electrical balance duplexer has multiple impedance gradients and multiple impedance tuners. The electrical balance duplexer transmits an outgoing signal from a transmitter during a transmission mode when a first set of impedance gradients of the multiple impedance gradients is operating in a first impedance state and a first set of impedance tuners of the multiple impedance tuners is operating in a second state. The electrical balance duplexer isolates the outgoing signal from a receiver during the transmission mode when a second set of impedance gradients of the multiple impedance gradients and a second set of impedance tuners of the multiple impedance tuners are operating in the second impedance state.

A front end module includes: a first antenna terminal; a second antenna terminal; a switch including a plurality of first side terminals on a first side and a plurality of second side terminals on a side opposite to the first side, each of the first side terminals being connected to one of the first antenna terminal and the second antenna terminal; a first filter connected to the first antenna terminal; a second filter connected to the first antenna terminal; a third filter connected to one of the second side terminals; and a fourth filter connected to one of the second side terminals. The third filter and the fourth filter are connected to one of the first antenna terminal and the second antenna terminal.

Disclosed is a filter and amplification circuit including a first switch with a single input and multiple outputs, a second switch with multiple inputs and a single output, and signal paths (each with an amplifier and band pass filter) between the outputs of the first switch and the inputs of the second switch, respectively. During filtering, the input of the first switch receives a radio frequency (RF) signal and filtering is performed through a combination of a selected signal path (which is active and has its amplifier enabled) and non-selected signal paths (which are passively coupled to the selected signal path and have their amplifiers disabled). Isolation is provided by the switches (e.g., solid-state switches) and the amplifiers, ensuring that the filtered RF signal at the single output of the second switch has a desired high spurious-free dynamic range (SFDR). Also disclosed are a test system and associated methods.

A signal switch includes a first transistor coupled between first and second nodes, a plurality of second transistors coupled in series between the first and second nodes and in parallel with the first transistor, and a first shunt path including a first shunt transistor and a first inductor connected in series between a reference node and a first connection point between two of the plurality of second transistors.

An example of a signal switch includes a first transistor coupled between first and second nodes, a plurality of second transistors coupled in series between the first and second nodes, in parallel with the first transistor, a third transistor coupled between the first node and a third node, and a plurality of fourth transistors coupled in series between the first and third nodes, in parallel with the third transistor. The signal switch further includes a first shunt path including a first shunt transistor and a first inductor connected in series between a reference node and a first connection point between two of the plurality of second transistors, and a second shunt path including a second shunt transistor and a second inductor connected in series between the reference node and a second connection point between two of the plurality of fourth transistors.