Filter arrangement

A filter arrangement comprising a balanced amplifier having an inverting input, a non-inverting input, an inverting output and a non-inverting output, at least a first input circuit arranged between a first input terminal and the inverting input, at least a second input circuit arranged between a second input terminal and the non-inverting input, a first feedback circuit arranged between the non-inverting output and the inverting input, and a second feedback circuit arranged between the inverting output and the non-inverting input, said first and second input circuits each comprising a substantially identical first circuit element and said first and second feedback circuits each comprising a substantially identical second circuit element, one of said two circuit elements being a capacitor and the other circuit element being a resistor, the magnitude of at least one of said two circuit elements being adjustable, characterized in that one circuit element comprises a junction capacitor and further comprising a bias-current source connected to the inverting input and to the non-inverting input for adjusting the capacitance of the junction capacitor connected to the relevant input.