Active radio frequency mixer circuit with feedback
AssigneeNokia Mobile Phones Ltd.
InventorJohn B. Groe
Life of this patent
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Abstract
An active mixer circuit, and an associated method, includes a feedback element which increases the linearity of the mixer circuit so that the mixer circuit is operable over a wider dynamic range than typically permitted of conventional, active mixer circuits. The mixer circuit includes a transconductance stage including a pair of transconductance transistors. Signals are applied through both of the transconductance transistors in parallel. The feedback element is coupled to an output side of a first of the transconductance transistors. And, a mixing stage is coupled to an output side of a second of the transconductance transistors.
Claims20
A mixer circuit for mixing together an input signal with a mixing signal to form a mixed signal, said mixer circuit comprising:
- an amplifying stage having a first transistor having a first input side and a first output side, the first input side coupled to receive the input signal and a second transistor having a second input side and a second output side, the second input side coupled to receive the input signal, the first transistor for generating a first amplified signal at the first output side and the second transistor for generating a second amplified signal at the second output side;
- a feedback element coupled between the first output side and the input side of the first transistor of said amplifying stage;
- and
- a mixing element coupled to the second output side of the second transistor of said amplifying stage and coupled to receive the mixing signal, said mixing element for mixing together the second amplified signal and the mixing signal, thereby to form the mixed signal.
In a radio receiver operable to receive a downlink signal transmitted thereto, an improvement of a mixer circuit coupled to receive a receive signal representative of the downlink signal and a down-mixing signal, said mixer circuit forming a down-mixed signal therefrom, said mixer circuit comprising:
- an amplifying stage having a first transistor having a first input side and a first output side, the first input side coupled to receive the receive signal and a second transistor having a second input side and a second output side, the second input side coupled to receive the receive signal, the first transistor for generating a first amplified signal at the first output side and the second transistor for generating a second amplified signal at the second output side;
- a feedback element coupled between the first output side and the input side of the first transistor of said amplifying stage;
- and
- a mixing element coupled to the second output side of the second transistor of said amplifying stage and coupled to receive the down-mixing signal, said mixing element for mixing together the second amplified signal and the down-mixing signal, thereby to form the down-mixed signal.
In a radio transmitter, an improvement of a mixer circuit having a transmit signal applied to a first input thereof and a mixing signal applied to a second input thereof, said mixer circuit for forming an up-mixed signal, said mixer circuit comprising:
- an amplifying stage having a first transistor having a first input side and a first output side, the first input side coupled to receive the transmit signal and a second transistor having a second input side and a second output side, the second input side coupled to receive the transmit signal, the first transistor for generating a first amplified signal at the first output side and the second transistor for generating a second amplified signal at the second output side;
- a feedback element coupled between the first output side and the input side of the first transistor of said amplifying stage;
- and
- a mixing element coupled to the second output side of the second transistor of said amplifying stage and coupled to receive the up-mixing signal, said mixing element for mixing together the second amplified signal and the up-mixing signal, thereby to form the mixed signal.
A method for mixing together an input signal with a mixing signal to form a mixed signal, said method comprising:
- applying, in parallel, the input signal to a first transistor and to a second transistor of an amplifying stage, the first transistor having a first input side and a first output side and the second transistor having a second input side and a second output side;
- generating a first amplified signal at the first output side of the first transistor;
- generating a second amplified signal at the second output side of the second transistor;
- coupling the first amplified signal generated at the first output side of the first transistor by way of a feedback element to the first input side of the first amplifier;
- applying the second amplified signal to a mixing element;
- applying the mixing signal to the mixing element;
- mixing together the second amplified signal applied to the mixing element with the mixing signal, thereby to form the mixed signal.
Dependencies are inferred from the claim text.