Harmonic rejection mixer architecture with reduced sensitivity to gain and phase mismatches
First Claim
1. A radio frequency (RF) mixer for transforming a frequency of an RF input signal, the RF mixer comprising:
- a first switching stage having a first plurality of switches configured to sample the RF input signal to produce a sampled RF signal in response to a first plurality of switching signals; and
a second switching stage having a second plurality of switches connected in parallel, the second plurality of switches being configured to receive the sampled RF signal and produce a plurality of frequency translated output signals in response to a second plurality of switching signals;
wherein each of the second plurality of switching signals is a phase-shifted version of a local oscillator (LO) signal having a LO frequency, the LO frequency being substantially equal to a frequency of the RF signal,wherein the first plurality of switching signals have a frequency N times higher than the LO frequency, N being an integer greater than unity.
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Abstract
A harmonic rejection mixer includes a first scaling circuit for scaling an RF signal to generate a plurality of scaled RF signals, a first switching stage for sampling the scaled RF signals using a first plurality of switching signals, and a second mixing stage for mixing the sampled RF signals with a second plurality of switching signals to generate a plurality of frequency translated signals having different phases. A combiner adds the frequency translated signals together to generate a first plurality of baseband versions of the RF signal. A first amplifier stage processes the first plurality of baseband versions to generate a second plurality of baseband versions. The mixer further includes a second scaling circuit for scaling the second plurality of baseband versions and a second amplifier stage to generate an in-phase baseband signal and a quadrature baseband signal from the scaled second plurality of baseband versions.
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Citations
28 Claims
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1. A radio frequency (RF) mixer for transforming a frequency of an RF input signal, the RF mixer comprising:
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a first switching stage having a first plurality of switches configured to sample the RF input signal to produce a sampled RF signal in response to a first plurality of switching signals; and a second switching stage having a second plurality of switches connected in parallel, the second plurality of switches being configured to receive the sampled RF signal and produce a plurality of frequency translated output signals in response to a second plurality of switching signals; wherein each of the second plurality of switching signals is a phase-shifted version of a local oscillator (LO) signal having a LO frequency, the LO frequency being substantially equal to a frequency of the RF signal, wherein the first plurality of switching signals have a frequency N times higher than the LO frequency, N being an integer greater than unity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A harmonic rejection mixer comprising:
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a first scaling circuit having a first plurality of weighting factors and configured to scale an amplitude of an RF signal using the weighting factors and generate a plurality of scaled RF signals; a first switching stage having a plurality of first switches connected in parallel and configured to sample the plurality of scaled RF signals and generate a plurality of sampled RF signals in response to a first plurality of switching signals; and a second mixing stage having a plurality of second switches connected in parallel and configured to mix the plurality of sampled RF signals and generate a plurality of frequency translated output signals in response to a second plurality of switching signals. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of down-mixing a radio frequency (RF) signal, the method comprising:
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sampling the RF signal with a first plurality of switching signals to generate a sampled RF signal; and mixing the sampled RF signal with a different one of a second plurality of parallel switching signals to produce a plurality of frequency translated output signals; wherein each of the second plurality of switching signals is a phase-shifted version of a local oscillator (LO) signal having an LO frequency, wherein a frequency of the first plurality of switching signals is N times higher than the LO frequency, N being an integer greater than unity. - View Dependent Claims (21, 22, 23)
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24. A method of down-mixing a voltage-domain RF signal having a RF frequency, the method comprising:
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converting the voltage-domain RF signal into a current-domain RF signal; scaling the current-domain RF signal using a plurality of resistive elements coupled in parallel to generate a plurality of weighted RF signals, each of the resistive elements representing a weighting factor; sampling the weighted RF signals with a first plurality of switching signals to generate a plurality of sampled RF signals; mixing the plurality of sampled RF signals with a second plurality of switching signals to generate a plurality of frequency translated signals; and combining the plurality of frequency translated signals to generate an in-phase baseband signal and a quadrature baseband signal. - View Dependent Claims (25)
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26. A method of down-mixing a radio frequency (RF) signal, the method comprising:
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scaling the RF signal using a first plurality of weighting factors to generate a plurality of weighted RF signals; sampling the plurality of weighted RF signals using a first plurality of switch signals to generate a plurality of sampled RF signals; and mixing the plurality of sampled RF signals with a second plurality of switch signals to generate a plurality of frequency translated output signals; wherein the second plurality of switch signals comprises a plurality of phase-shifted versions of a local oscillator signal having a frequency that is about a frequency of the RF signal. - View Dependent Claims (27, 28)
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Specification