CMOS frequency conversion using dual mixers for sideband suppression
First Claim
1. A frequency conversion circuit with sideband suppression comprising:
- (a) a first mixer for receiving an in-phase signal (IFi) and driven by a local oscillator having an in-phase oscillator signal (LOi), and producing sideband signals (LO+IFi, LO−
IFi), (b) a second mixer for receiving a quadrature phase frequency signal (IFq) relative to the in-phase signal and driven by a local oscillator having a quadrature oscillator signal (LOq) relative to the in-phase oscillator signal, and producing two sidebands (LO+IFq, LO−
IFq), one of the sidebands from the second mixer being 180°
out of phase with respect to the same sideband from the first mixer, and (c) a signal combiner for receiving and combining the two sidebands in the first mixer and the two sidebands from the second mixer, the signal combiner suppressing one sideband and enhancing the other sideband.
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Abstract
Disclosed is a frequency conversion circuit with sideband suppression in which a first mixer receives an in-phase signal (IFi) and is driven by a local oscillator having an in-phase (0°) oscillator signal (LOi), and produces two sideband signals (LO+IF, LO−IF). A second mixer receives a quadrature phase frequency signal (IFq+) and is driven by a local oscillator having a quadrature (180°) oscillator signal (LOq), and produces two sideband signals (LO+IFq, LO−IFq). One of the sidebands from the second mixer is 180° out of phase with respect to the same sideband from the first mixer. A signal combiner then receives and combines the two sidebands from the first mixer and the two sidebands from the second mixer, the signal combiner suppressing one sideband and enhancing the other sideband. In preferred embodiments, the mixers comprise MOSFET transistors and the signal combiner comprises capacitive elements.
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Citations
6 Claims
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1. A frequency conversion circuit with sideband suppression comprising:
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(a) a first mixer for receiving an in-phase signal (IFi) and driven by a local oscillator having an in-phase oscillator signal (LOi), and producing sideband signals (LO+IFi, LO−
IFi),(b) a second mixer for receiving a quadrature phase frequency signal (IFq) relative to the in-phase signal and driven by a local oscillator having a quadrature oscillator signal (LOq) relative to the in-phase oscillator signal, and producing two sidebands (LO+IFq, LO−
IFq), one of the sidebands from the second mixer being 180°
out of phase with respect to the same sideband from the first mixer, and(c) a signal combiner for receiving and combining the two sidebands in the first mixer and the two sidebands from the second mixer, the signal combiner suppressing one sideband and enhancing the other sideband. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification