Apparatus and method of differential IQ frequency up-conversion
First Claim
1. An apparatus, comprising:
- an in-phase channel including;
a first pair of impedances configured to receive a first differential signal, anda first switch configured to sample said first differential signal by shorting together corresponding outputs of said first pair of impedances in response to a first control signal; and
a quadrature channel including;
a second pair of impedances configured to receive a second differential signal, anda second switch configured to sample said second differential signal by shorting together corresponding outputs of said second pair of impedances in response to a second control signal,wherein said outputs of said first pair of impedances are wire-ored with said outputs of said second pair of impedances, resulting in an IQ output.
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Abstract
A balanced transmitter up-converts I and Q baseband signals directly from baseband-to-RF. The up-conversion process is sufficiently linear that no IF processing is required, even in communications applications that have stringent requirements on spectral growth. In operation, the balanced modulator sub-harmonically samples the I and Q baseband signals in a balanced and differential manner, resulting in harmonically rich signal. The harmonically rich signal contains multiple harmonic images that repeat at multiples of the sampling frequency, where each harmonic contains the necessary information to reconstruct the I and Q baseband signals. The differential sampling is performed according to a first and second control signals that are phase shifted with respect to each other. In embodiments of the invention, the control signals have pulse widths (or apertures) that operate to improve energy transfer to a desired harmonic in the harmonically rich signal. A bandpass filter can then be utilized to select the desired harmonic of interest from the harmonically rich signal.
860 Citations
26 Claims
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1. An apparatus, comprising:
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an in-phase channel including; a first pair of impedances configured to receive a first differential signal, and a first switch configured to sample said first differential signal by shorting together corresponding outputs of said first pair of impedances in response to a first control signal; and a quadrature channel including; a second pair of impedances configured to receive a second differential signal, and a second switch configured to sample said second differential signal by shorting together corresponding outputs of said second pair of impedances in response to a second control signal, wherein said outputs of said first pair of impedances are wire-ored with said outputs of said second pair of impedances, resulting in an IQ output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 26)
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12. An apparatus for up-converting an in-phase (I) baseband signal having a first component and a second component and a quadrature (Q) baseband signal having a third component and a fourth component, comprising:
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an in-phase channel configured to up-convert the I baseband signal using a first control signal by shorting together said first component and said second component to provide said up-converted I signal; a quadrature channel configured to up-convert the Q baseband signal using a second control signal by shorting together said third component and said fourth component to provide said up-converted Q signal; and a wire-or connection between an output of said in-phase channel and an output of said quadrature channel to combine said up-converted I signal and said up-converted Q signal. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method of up-converting a first differential baseband signal and a second differential baseband signal, comprising:
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receiving a first differential baseband signal and a second differential baseband signal; generating a first control signal and a second control signal having a common frequency, wherein said second control signal is phase-shifted relative to said first control signal; shorting together differential components of said first differential baseband signal according to said first control signal resulting in a first up-converted signal; shorting together differential components of said second differential baseband signal according to said second control signal resulting in a second up-converted signal; and combining said first up-converted signal with said second up-converted signal using a wire-or connection. - View Dependent Claims (20, 21, 22)
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23. A method of up-converting a first baseband signal and a second baseband signal, comprising:
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receiving a first baseband signal and a second baseband signal; generating a first control signal and a second control signal having a common frequency, wherein said second control signal is phase-shifted relative to said first control signal; sampling said first baseband signal by shorting together corresponding components of said first baseband signal according said first control signal resulting in a first up-converted signal; sampling said second baseband signal by shorting together corresponding components of said second baseband signal according to said second control signal resulting in a second up-converted signal; and combining said first up-converted signal with said second up-converted signal using a wire-or connection. - View Dependent Claims (24, 25)
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Specification