Offset correction for down-conversion mixers
Offset correction for down-conversion mixers
A direct conversion receiver includes a detector that provides a measure of bias offset that is caused by component mismatches in the direct conversion mixer, and a corrective network that reduces the bias offset based on this measure. The direct conversion mixer demodulates a radio-frequency (RF) input signal via mixing with a local-oscillator (LO) signal to provide a differential baseband output signal. A differential peak detector compares the peak signal value at each side of the mixer's differential output, and a differential integrator averages the difference between these peak signal values to provide the measure of bias offset. The corrective network adds a correction offset to each of the local oscillator local oscillator paths on each of the switching pairs that provide the differential output, but opposite to the local oscillator connections. By applying the correction offset to the opposing transistor in each pair, the difference in switching time between the pairs is reduced, and, correspondingly, the differential-mode leakage from the local oscillator to the RF input stage is reduced.
US Patent 7536165B2
19 May 2009
Redman-White, William
d5376167-c925-460f-8e9c-13bffda8e0bf
Redman-White, William
(Inventors)
(2009)
Offset correction for down-conversion mixers.
US Patent 7536165B2.
Abstract
A direct conversion receiver includes a detector that provides a measure of bias offset that is caused by component mismatches in the direct conversion mixer, and a corrective network that reduces the bias offset based on this measure. The direct conversion mixer demodulates a radio-frequency (RF) input signal via mixing with a local-oscillator (LO) signal to provide a differential baseband output signal. A differential peak detector compares the peak signal value at each side of the mixer's differential output, and a differential integrator averages the difference between these peak signal values to provide the measure of bias offset. The corrective network adds a correction offset to each of the local oscillator local oscillator paths on each of the switching pairs that provide the differential output, but opposite to the local oscillator connections. By applying the correction offset to the opposing transistor in each pair, the difference in switching time between the pairs is reduced, and, correspondingly, the differential-mode leakage from the local oscillator to the RF input stage is reduced.
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Published date: 19 May 2009
Organisations:
Nanoelectronics and Nanotechnology
Identifiers
Local EPrints ID: 337763
URI: http://eprints.soton.ac.uk/id/eprint/337763
PURE UUID: 135a4e32-6ba5-4ca4-9998-4effcdcf3c06
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Date deposited: 02 May 2012 13:58
Last modified: 14 Mar 2024 10:57
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Inventor:
William Redman-White
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