Double-balanced mixer circuit.

摘要

Two cross-coupled differential amplifiers (T1, T2 and T3, T4) have a common first (1) and a common second (2) base terminal to which an oscillator signal is applied. Via transformer (12) the radio-frequency signal from a source (10) having an impedance (11) is applied to a balanced commonbase circuit comprising the transistors (T5, T6), whose collectors are coupled to the common-emitter terminals (3) and (4) of the differential amplifiers (T1, T2; T3, T4) respectively. With such a mixer circuit a better intermodulation and noise behaviour is obtained when compared with the usual differential amplifier instead of the balanced common-base circuit.