second control input 12 b in addition the inventive mixer includes a first impedance element z 21 connected between the first intermediate node 14 a and the first intermediate frequency output 16 a and a second impedance element z 24 connected between the second intermediate node 14 b and the second intermediate frequency output 16 b in a preferred embodiment of the present invention the mixer is designed completely balanced and further includes a third positive feedback element c 21 connected between a third intermediate node 20 a and the first control input 12 a and a fourth positive feedback element c 34 connected between a fourth intermediate node 20 b of the second transistor circuit 10 b and the first control input 12 a furthermore there are also a third impedance element z 22 connected between the third intermediate node 20 a and the second intermediate frequency output 16 b and a fourth impedance element z 23 connected between the fourth intermediate node 20 b and the first intermediate frequency output 16 a the rf signal is supplied in a balanced way namely to the control terminals of two transistors t 11 and t 12 also preferably implemented as bipolar transistor which form a transistor stage and operate to modulate the current supplied by the current source idc according to the rf signal the positive feedback effect is achieved because as the potential u2014 with respect to the second transistor circuit.