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 . <EOS>