Self-oscillating push=pull mixer for TV - has inputs and outputs of transistors connected to two capacitive voltage dividers to attain balanced characteristics

摘要

The mixing stage uses transistors of the same conduction type and is balanced both at its input and output. Harmonics are avoided and cross modulation is low. A capacitance voltage divider (7, 7', 1, 1') is connected to the input and output of the transistors (13-14) forming the stage's pushpull mixer. The inductor in the IF resonant circuit comprises a transformer (53) with two symmetric bifilar windings (15, 16). Each winding is connected at one end to the collector of one of the transistors and at the other to one of the mixer's unbalanced IF output terminals.