Abstract: In order to facilitate its construction as in integrated circuit, the inductive elements of two resonant circuits in a band-pass filter are each constituted by a first port of a respective gyrator circuit (22, 23 and 24, 25 respectively) the second port of which is loaded by a capacitor (3 and 6 respectively). The first ports, across which are connected capacitors (1 and 3 respectively), are connected by a signal path one to the other, as are the second ports, in such manner that a loop is formed comprising the two gyrator circuits and the two signal paths, enabling bilateral coupling of the two gyrator circuits to be obtained by coupling otherwise unused outputs (24+ and 22+) to otherwise unused inputs (22- and 24- respectively) of two-input two-output voltage-controlled current sources (22, 24) which form part of each gyrator circuit.