A filter system having an infinite impulse response having real input and output, wherein the transfer function of the filter system includes at least one pair of poles and/or zeros respectively complex conjugates, and - wherein the real input is fed to a first adder, - an output of the first adder is split and connected to a second adder and a first delay, and - an output of the first delay is split and connected to a first multiplier having a first coefficient, the output of which is connected to the first adder, to a second multiplier having a second coefficient, the output of which is connected to the second adder, and to a third multiplier having a third coefficient, the output of which is connected to a third adder, and - an output of the second adder is fed to a fourth adder, and - an output of the fourth adder is split and connected to a second delay and a fifth adder, and - an output of the second delay is split and connected to a fourth multiplier having the first coefficient, the output of which is connected to the fourth adder, to a fifth multiplier having the second coefficient, the output of which is connected to the fifth adder and to a sixth multiplier having a fourth coefficient, the output of which is connected to the third adder, and - an output of the third adder is fed to a third delay, and - an output of the third delay is split and connected to a seventh multiplier having the first coefficient, the output of which is connected to the third adder, to an eighth multiplier having the third coefficient, the output of which is connected to the fifth adder, and to a ninth multiplier having a fifth coefficient, the output of which is connected to the fourth adder, and - the fourth coefficient and the fifth coefficient being equal with opposite sign to each other, and - an output of the fifth adder is fed to a tenth multiplier having a gain (K, K 2), the output of the tenth multiplier forming the real output of the filter system. - wherein the real input is fed to a first adder, - an output of the first adder is split and connected to a second adder and a first delay, and - an output of the first delay is split and connected to a first multiplier having a first coefficient, the output of which is connected to the first adder, to a second multiplier having a second coefficient, the output of which is connected to the second adder, and to a third multiplier having a third coefficient, the output of which is connected to a third adder, and - an output of the second adder is fed to a fourth adder, and - an output of the fourth adder is split and connected to a second delay and a fifth adder, and - an output of the second delay is split and connected to a fourth multiplier having the first coefficient, the output of which is connected to the fourth adder, to a fifth multiplier having the second coefficient, the output of which is connected to the fifth adder and to a sixth multiplier having a fourth coefficient, the output of which is connected to the third adder, and - an output of the third adder is fed to a third delay, and - an output of the third delay is split and connected to a seventh multiplier having the first coefficient, the output of which is connected to the third adder, to an eighth multiplier having the third coefficient, the output of which is connected to the fifth adder, and to a ninth multiplier having a fifth coefficient, the output of which is connected to the fourth adder, and - the fourth coefficient and the fifth coefficient being equal with opposite sign to each other, and - an output of the fifth adder is fed to a tenth multiplier having a gain (K, K 2), the output of the tenth multiplier forming the real output of the filter system.