A circuit includes a signal path having a node between a signal path input and a signal path output. A first inductive element is connected between the signal path input and the node and a first capacitive element whose capacitance is variably adjustable is connected between the node and the signal path output. A second variable-capacitance capacitive element is connected between the signal path input and ground. A second inductive element is connected between the node and ground, and a third inductive element is connected between the signal path output and ground.