Automatic selection of compensation value to reduce IM2 product in mixed signal output
First Claim
1. A calibration apparatus for automatically selecting a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, the calibration apparatus comprising:
- a mixer to output a mixed signal;
a detector to detect an IM2 product in samples corresponding to the mixed signal; and
a compensation determination circuit to do the following automatically,to apply a plurality of candidate values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal,to evaluate samples from the detector corresponding to the plurality of candidate values, respectively, andto select one among the plurality candidate values as the compensation value,wherein the detector includes,an IM2 sampler to produce the samples corresponding to the mixed signal and to generate an indication of the magnitude of an IM2 product in the samples, respectively, anda monotonicity change sensor to detect if there is a change in a monotonic progression of samples output by the IM2 sampler.
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Accused Products
Abstract
An apparatus, for automatically selecting a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, may include: a mixer to output a mixed signal; a detector to detect an product in samples corresponding to the mixed signal; a compensation determination circuit to do the following automatically, to apply a plurality of candidate values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal, to evaluate samples from the detector corresponding to the plurality, respectively, and to select one among the plurality candidate values as the compensation value.
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Citations
24 Claims
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1. A calibration apparatus for automatically selecting a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, the calibration apparatus comprising:
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a mixer to output a mixed signal; a detector to detect an IM2 product in samples corresponding to the mixed signal; and a compensation determination circuit to do the following automatically, to apply a plurality of candidate values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal, to evaluate samples from the detector corresponding to the plurality of candidate values, respectively, and to select one among the plurality candidate values as the compensation value, wherein the detector includes, an IM2 sampler to produce the samples corresponding to the mixed signal and to generate an indication of the magnitude of an IM2 product in the samples, respectively, and a monotonicity change sensor to detect if there is a change in a monotonic progression of samples output by the IM2 sampler. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A calibration apparatus for automatically calibrating a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, the apparatus comprising:
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a mixer to output a mixed signal; an IM2 sampler to produce a sample corresponding to the mixed signal and to generate an indication of the magnitude of an IM2 product in the sample; a monotonicity change sensor to detect if there is a change in a monotonic progression of samples output by the IM2 sampler; and a correction generator to supply a plurality of values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal.
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16. A method for automatically selecting a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, the method comprising:
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providing samples corresponding to a mixed signal; detecting an IM2 product in the samples; performing the following automatically, applying a plurality of candidate values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal, evaluating the samples corresponding to the plurality of candidate values, respectively, and selecting one among the plurality candidate values as the compensation value, wherein the step of detecting includes, generating an indication of the magnitude of an IM2 product in the samples, respectively, and detecting if there is a change in a monotonic progression of the samples. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A calibration apparatus for automatically selecting a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, the calibration apparatus comprising:
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a mixer to output a mixed signal; a detector to detect an IM2 product in samples corresponding to the mixed signal; and a compensation determination circuit to do the following automatically, to apply a plurality of candidate values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal, to evaluate samples from the detector corresponding to the plurality of candidate values, respectively, and to select one among the plurality candidate values as the compensation value, wherein the compensation determination circuit includes, a code generator to generate a plurality of values of a code used to shape the mixer-control signal, a signal shaper to shape the mixer-control signal according to the values of the code, respectively, a delay unit to delay an ith value of the code and so obtain an (i−
1)th value of the code,a memory to hold the (i−
1)th value of the code, anda switching circuit, responsive to detection of a change by a monotonicity change sensor of the detector, to apply the contents of the memory to the signal shaper.
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23. A calibration apparatus for automatically selecting a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, the calibration apparatus comprising:
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a mixer to output a mixed signal; a detector to detect an IM2 product in samples corresponding to the mixed signal; a compensation determination circuit to do the following automatically, to apply a plurality of candidate values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal, to evaluate samples from the detector corresponding to the plurality of candidate values, respectively, and to select one among the plurality candidate values as the compensation value; and a test signal generator to generate a test signal and to provide the same to a node which represents an external output terminal, wherein the test signal generator includes, a mixer to mix a local oscillation signal and a two-tone signal and so obtain a precursor signal, and a Balun circuit to unbalance the precursor signal and obtain the test signal.
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24. A method for automatically selecting a compensation value usable to reduce a second order intermodulation (IM2) product in an output signal of a mixer, the method comprising:
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providing samples corresponding to a mixed signal; detecting an IM2 product in the samples; performing the following automatically, applying a plurality of candidate values of a mixer-control signal to the mixer, the mixer-control signal affecting a magnitude of an IM2 product in the mixed signal, evaluating the samples corresponding to the plurality of candidate values, respectively, and selecting one among the plurality candidate values as the compensation value; and generating the plurality of values of the mixer-control signal so as to variously affect a magnitude of an IM2 product in the mixed signal, respectively, wherein the generating step includes, forming a plurality of values of a code used to shape the mixer-control signal, shaping the mixer-control signal according to the values of the code, respectively, delaying an ith value of the code and so obtaining an (i−
1)th value of the code,storing the (i−
1)th value of the code, andselectively using, responsive to detection of a change in a monotonic progression of the samples, the stored (i−
1) th value of the code.
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Specification