A circuit includes a current sensing circuit comprising a current input terminal coupled to an input port, a current output terminal coupled to a transmitted port, and a current sensing output terminal configured to provide a current sensing signal proportional to a current flowing between the current input terminal and the current output terminal. The circuit further includes a voltage sensing circuit having a voltage input terminal coupled to the transmitted port and a voltage sensing output terminal configured to provide a voltage sensing signal proportional to a voltage at the transmitted port. A combining circuit has a first input coupled to the current sensing output terminal, a second input coupled to the voltage sensing output terminal, and a combined output node coupled to an output port.