The present invention includes a mixer circuit integrating a
voltage-to-currrent conversion in the same stage. A mixer device 20 of a
transmission system comprises a pair of transistors 41 and 42 forming a
differential circuit having two differential inputs receiving a carrier
V.sub.LO, two differential current outputs delivering a differential
output current and a common current output whose current is equal to the
sum of the differential output currents; a current-to-voltage conversion
element 47 coupled to the common current output of the pair of
transistors; an amplifier 30 having a positive input receiving the
modulating signal, a negative feedback input coupled to the
current-to-voltage conversion element, and an output coupled to each of
the differential inputs of the pair of transistors.