Abstract: An imperfectly filtered d.c. operating voltage is applied to an electrode, such as the emitter electrode of an output transistor, an input signal being applied to another electrode, such as the base electrode of the transistor. The ripple component thereby induced at the collector electrode of this transistor is cancelled by adjusting to a value exactly equal thereto, the complementary ripple component of the d.c. operating voltage applied to the collector electrode.

Abstract: A phase control circuit includes an amplifier having a signal combining output, an inverting input signal supplied via a first coupling path with signals to be phase controlled, and a non-inverting input supplied via a second coupling path with such signals, the second coupling path including a reactive element and a variable admittance device. The variable admittance device comprises an operational transconductance amplifier exhibiting a controllable linear transconductance characteristic and an output admittance which varies proportionally to the transconductance in response to applied bias current. Variation of the bias current in a predetermined manner produces a corresponding variation in phase shift imparted to signals provided at the signal combining output.