Abstract: A filter is provided with a capacitive element 6 arranged in shunt across the input, two series-arranged inductive branches 3 and 4 between which a shunting inductive branch 5 is arranged and a capacitive element 7 arranged in shunt across the output. One of the two series-arranged branches includes, in series from the central point 30, a first inductance 3A and a second inductance 3B connected at a point 31 and a capacitor 8 is added in the branch. The shunting branch includes two inductances 5A and 5B which are arranged in series and are interconnected at a point 32. Two diodes, used as switches S1 and S2, one of which is blocked when the other is conducting, are arranged, one between the point 31 and the extermity of series-arranged inductive branch arranged opposite the central point, and the other between the same point 31 and the point 32.