CIRCUIT AND METHOD FOR INTERFERENCE REDUCTION Russian patent published in 2014 - IPC H04B1/04 

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to radio engineering and can be used in radio frequency transmitter circuits for interference reduction. A radio frequency transmitter comprises an amplifier, an antenna port, an isolator adapted to isolate the output of the amplifier from an interfering signal of the antenna port, a linearisation loop and a transmission line comprising a first part (coupling a signal source to the input of the amplifier), a second part (coupling the output of the amplifier to the input of the isolator) and a third part (coupling the output of the isolator to the antenna port). The linearisation loop is adapted to reduce non-linearity of the isolator and comprises a first directional coupler coupled to the third part of the transmission line, a loop impedance, and at least one additional linearisation loop element adapted to adjust a linearisation signal and to feed the adjusted linearisation signal to the transmission line. The invention also enables to adjust the linearisation and feed the adjusted linearisation signal to the transmission line. The radio frequency transmitter also comprises an interference reducing circuit adapted to reduce an influence of the interfering signal on the linearisation loop.

EFFECT: reducing interference and/or increasing linearity in a radio frequency transmitter.

7 cl, 8 dwg