Discrete time polyphase mixer
AssigneeRF Micro Devices, Inc.
InventorsStephen Allott, Thomas Gregory McKay
Life of this patent
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Abstract
Embodiments of a radio frequency (RF) circuit provide translational filtering in accordance with an input impedance response that is an impedance image of a reactive circuit impedance response from a polyphase reactive circuit. The RF circuit may include a first mixer circuit that provides a first frequency offset for the impedance image and a second mixer circuit that provides an additional frequency offset. Accordingly, the second mixer circuit may allow for adjustments to a total frequency offset of the impedance image. The second mixer circuit may also be configured so that the impedance image rejects a negative frequency impedance response of the reactive circuit impedance response.
Claims23
A radio frequency (RF) circuit comprising:
- a first mixer circuit configured to receive a first oscillation signal operating at approximately a first oscillation frequency and an input signal, wherein the first mixer circuit is configured to present an input impedance to the input signal in accordance with an input impedance response of the first mixer circuit;
- a second mixer circuit operably associated with first mixer circuit and being configured to receive a second oscillation signal operating at approximately a second oscillation frequency;
- and
- a reactive circuit having a reactive circuit impedance response, the reactive circuit being operably associated with the second mixer circuit, such that the input impedance response of the first mixer circuit is an impedance image of the reactive circuit impedance response, wherein the first mixer circuit is operable to provide a first frequency offset between the impedance image and the reactive circuit impedance response based on the first oscillation frequency, and the second mixer circuit is operable to provide an additional frequency offset between the impedance image and the reactive circuit impedance response based on the second oscillation frequency.
A radio frequency (RF) circuit comprising:
- a polyphase reactive circuit comprising a first polyphase reactive device and a second polyphase reactive device, wherein the polyphase reactive circuit has a reactive circuit impedance response with a positive frequency impedance response and a negative frequency impedance response;
- a first mixer circuit having a first input impedance response wherein the first mixer circuit is operable to mix a first in-phase signal with a first oscillation signal and a first quadrature phase signal with a second oscillation signal to generate a second in-phase signal, the first mixer circuit being further operable mix the first in-phase signal with the second oscillation signal and to mix an inverse of the first quadrature phase signal with the first oscillation signal to generate a second quadrature phase signal, the first oscillation signal and the second oscillation signal operating at approximately a first oscillation frequency and a phase difference between the first oscillation signal and the second oscillation signal is such that the second oscillation signal is substantially orthogonal to the first oscillation signal;
- and
- the first polyphase reactive device being operably associated with the first mixer circuit to receive the second in-phase signal and the second polyphase reactive device being coupled to receive the second quadrature phase signal such that the first input impedance response is a first impedance image of the reactive circuit impedance response without the negative frequency impedance response and the first impedance image is offset from the reactive circuit impedance response based on the first oscillation frequency.
A method of presenting an input impedance to a source transmitting a radio frequency (RF) signal, comprising:
- providing a first input signal based on the RF signal;
- providing a first oscillation signal that operates at approximately a first oscillation frequency;
- providing a second oscillation signal that operates at approximately a second oscillation frequency;
- providing a reactive circuit having a reactive circuit impedance response;
- presenting the input impedance to the source in accordance with an input impedance response that is an impedance image of the reactive circuit impedance response, wherein presenting the input impedance to the first input signal comprises:
- mixing the first input signal with the first oscillation signal to offset the impedance image from the reactive circuit impedance response;
- mixing the first input signal with the second oscillation signal to further offset the impedance image from the reactive circuit impedance response.
A method of presenting an input impedance to a source transmitting a radio frequency (RF) signal comprising:
- providing a polyphase reactive circuit having a reactive circuit impedance response with a positive frequency impedance response and a negative frequency impedance response;
- presenting the input impedance to the source in accordance with an input impedance response that is an impedance image of the reactive circuit impedance response, wherein presenting the input impedance to the source includes the impedance image rejecting the negative frequency impedance response of the reactive circuit impedance response.
Dependencies are inferred from the claim text.