Multimode receiver with complex filter
AssigneeMStar Semiconductor, Inc.
InventorsThomas McKay, Jonathan Gowing, Stephen Allott, Cyril Valadon
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Abstract
One aspect of the present invention includes a radio frequency (RF) receiver having a first mixer and a second mixer. The first mixer may be an I-mixer and the second mixer a Q-mixer for downconverting the received RF signal. An impedance circuit is disposed between the first mixer and the second mixer to decouple the channels. In another aspect of present invention, the RF receiver includes a digital filter having at least one complex coefficient. The digital filter exhibits asymmetrical frequency response, and may be used to compensate the asymmetrical frequency response of another filter in the RF receiver.
Claims10
A radio frequency (RF) receiver comprising:
- a first set of mixers receiving an RF signal according to a first communication mode;
- a second set of mixers receiving the RF signal according to a second communication mode;
- wherein one of the first set and the second set of mixers comprises a first mixer and a second mixer,
- wherein a resistance circuit is disposed, and is always in a signal path, between each of the first mixer and the second mixer and a low noise amplifier (LNA),
- the RF receiver further comprising:
- a digital filter, including a complex filter coefficient, coupled to an output of one of the first and second set of mixers, wherein the digital filter has asymmetrical frequency response,
- wherein the complex filter coefficient is set dynamically,
- wherein the one of the first and second set of mixers to which the digital filter is coupled is coupled to a polyphase reactive circuit, and
- the RF receiver further comprising an additional filter including the polyphase reactive circuit, wherein the frequency response of the digital filter compensates for a frequency response of the additional filter.
A radio frequency (RF) receiver comprising:
- a first set of mixers and a second set of mixers receiving an RF signal, the first set of mixers being configured to receive the RF signal according to a first communication mode, and the second set of mixers being configured to receive the RF signal according to a second communication mode;
- a digital filter coupled to an output of one of the first set of mixers and the second set of mixers, wherein the digital filter has asymmetrical frequency response, wherein the asymmetrical frequency response is asymmetric in magnitude of the frequency response,
- wherein the digital filter includes a complex filter coefficient set dynamically,
- the RF receiver, further comprising:
- a polyphase reactive circuit coupled to the output of one of the first set of mixers and the second mixers set of mixers to which the digital filter is coupled;
- and
- an additional filter including the polyphase reactive circuit,
- wherein the frequency response of the digital filter compensates for a frequency response of the additional filter.
A method for improving frequency response symmetry of a radio frequency (RF) receiver, comprising:
- receiving an RF signal by a first set of mixers and a second set of mixers, the first set of mixers being configured to receive the RF signal according to a first communication mode, and the second set of mixers being configured to receive the RF signal according to a second communication mode;
- filtering, by a digital filter having asymmetrical frequency response, output of one of the first set of mixers and the second set of mixers, wherein the asymmetrical frequency response is asymmetric in magnitude of the frequency response, and wherein the digital filter includes a complex filter coefficient set dynamically;
- filtering, by an additional filter including a polyphase reactive circuit, the received RF signal;
- and
- compensating a frequency response of the additional filter by the frequency response of the digital filter.
Dependencies are inferred from the claim text.