Voltage control amplifier with differential transistor pairs - has emitter magnitude of one transistor pair as multiple of other transistor pair emitter magnitude

摘要

The transistor differential pairs are in common coupled to emitters, and an input signal is applied to a common connection for the emitters. The base potential of first transistors of the pairs is controlled for deriving a variable output signal by changing the current balance of the transistor pairs. The magnitude of the emitters of the first transistors (Q1,4) is a multiple of the emitter magnitude of the second transistors (Q2,3), with the multiple being a natural number exceeding unity. Pref. the emitter magnitude of the first transistors is the emitter surface in one transistor, possibly a surface of an emitter diffusion face on an integrated circuit chip. USE/ADVANTAGE - For noise suppression in FM tuner, or magnetic tape recorder, with attentuation adjustment without regard to control voltage changes.