HIGH-FREQUENCY MIXER STEP

摘要

PROBLEM TO BE SOLVED: To suppress a local oscillating component at the output terminal of a high-frequency mixer stage by forming the mixer stage of complementary transistors(TR) arranged in parallel on an AC voltage input stage and simultaneously setting both TRs in nonconductive and conductive states. SOLUTION: An addition push-pull high-frequency mixer stage formed of complementary TRs T1 and T2 which are connected to each other through their emitters is connected in parallel with an AC voltage input signal FS and a required DC voltage DSC is impressed upon the base of the n-type TR T2 . The p- and n-type TRs T1 and T2 , upon the bases of which the output of a local oscillator LQ is impressed, simultaneously become conductive and nonconductive states in the one cycle period of the signal ES. Therefore, the radiation of local oscillating signals through an antenna can be reduced even when the companding ratio of a high-frequency mixer stage is increased, because a local oscillating current is absorbed by the complementary TRs and the local oscillating component in the output signal AS of the mixer stage can be suppressed.