Apparatus and method of differential IQ frequency up-conversion
First Claim
1. An apparatus, comprising:
- a pair of impedances configured to receive a signal, anda switch configured to receive as an input for controlling the switch a control signal for controlling the switch at a desired sampling frequency that is equal to or less than twice the frequency of the input signal, the switch then sampling the signal in response to the control signal by shorting together corresponding outputs of the pair of impedances when the control signal is applied to close the switch, the sampling frequency providing a charge transfer which accumulates the charge transferred by the switch.
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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 necessary information to reconstruct the I and Q baseband signals. The differential sampling is performed according to control signals that are phase shifted with respect to each other. The control signals may 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.
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Citations
9 Claims
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1. An apparatus, comprising:
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a pair of impedances configured to receive a signal, and a switch configured to receive as an input for controlling the switch a control signal for controlling the switch at a desired sampling frequency that is equal to or less than twice the frequency of the input signal, the switch then sampling the signal in response to the control signal by shorting together corresponding outputs of the pair of impedances when the control signal is applied to close the switch, the sampling frequency providing a charge transfer which accumulates the charge transferred by the switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification