US 10,097,284 B1Granted

I/Q imbalance calibration apparatus, method and transmitter system using the same

AssigneeNational Chung Shan Institute of Science and Technology

InventorsYen-Cheng Kuan, Hung-Ting Chou

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Abstract

An I/Q imbalance calibration method includes sequentially inputting a first in-phase and quadrature signals calibration signal to a front-end circuit of the transmitter system to acquire and estimate a first and second calibration signal strengths sequentially, wherein a delta estimation is adopted; calculating an I/Q gain imbalance according to estimated first and second calibration signal strengths; sequentially inputting a second in-phase calibration signal and both of the second in-phase and quadrature calibration signal to the front-end circuit of the transmitter system to acquire and estimate a third and fourth calibration signal strengths sequentially, wherein an I/Q gain imbalance compensation is formed on the first in-phase and quadrature calibration signals to generate the second in-phase and quadrature calibration signals; and calculating an I/Q phase imbalance according to estimated third and fourth calibration signal strengths.

Claims20

Dependent claims

An in-phase/quadrature (I/Q) imbalance calibration apparatus used in a transmitter system operated in an I/Q imbalance calibration mode, comprising:

a calibration signal generator, used to selectively generate a first in-phase calibration signal, a first quadrature calibration signal, or both of the first in-phase and quadrature calibration signals;
an I/Q imbalance calibrator, electrically connected to the calibration signal generator, used to perform a I/Q gain imbalance compensation on the first in-phase and quadrature calibration signals to generate a second in-phase and quadrature calibration signals after receiving an I/Q gain imbalance, and selectively output the first in-phase calibration signal, the first quadrature calibration signal, the second in-phase calibration signal or both of the second in-phase and quadrature calibration signals to a front-end circuit of the transmitter system;
a signal strength acquiring circuit, electrically connected to the front-end circuit of the transmitter system, used to selectively acquire and output one of a first through fourth calibration signal strengths, wherein the first through fourth calibration signal strengths are corresponding to a first through fourth calibration signals respectively, and the first through fourth calibration signals are processed signals which the front-end circuit processes the first in-phase calibration signal, the first quadrature calibration signal, the second in-phase calibration signal and both of the second in-phase and quadrature calibration signals respectively;
and
an I/Q imbalance estimator, electrically connected to the signal strength acquiring circuit, used to selectively estimate one of the first through fourth calibration signal strengths by a delta estimation, calculate the I/Q gain imbalance according to an estimated first and second calibration signal strengths, calculate an I/Q phase imbalance according to an estimated third and fourth calibration signal strengths.

2 more elements

A transmitter system, comprises:

a baseband transmitter, having a calibration signal generator, in an in-phase/quadrature (I/Q) balance calibration mode, the calibration signal generator is used to selectively generate a first in-phase calibration signal, a first quadrature calibration signal, or both of the first in-phase and quadrature calibration signals;
an I/Q imbalance calibrator, electrically connected to the calibration signal generator, in the I/Q balance calibration mode, used to perform a I/Q gain imbalance compensation on the first in-phase and quadrature calibration signals to generate a second in-phase and quadrature calibration signals after receiving an I/Q gain imbalance, and selectively output the first in-phase calibration signal, the first quadrature calibration signal, the second in-phase calibration signal or both of the second in-phase and quadrature calibration signals;
a front-end circuit, electrically connected to the I/Q imbalance calibrator, in the I/Q balance calibration mode, used to selective receive and process the first in-phase calibration signal, the first quadrature calibration signal, the second in-phase calibration signal or both of the second in-phase and quadrature calibration signals to correspondingly generate one of a first through fourth calibration signals;
a signal strength acquiring circuit, electrically connected to the front-end circuit of the transmitter system, in the I/Q balance calibration mode, used to selectively acquire and output one of a first through fourth calibration signal strengths, wherein the first through fourth calibration signal strengths are corresponding to the first through fourth calibration signals respectively;
and
an I/Q imbalance estimator, electrically connected to the signal strength acquiring circuit, in the I/Q balance calibration mode, used to selectively estimate one of the first through fourth calibration signal strengths by a delta estimation, calculate the I/Q gain imbalance according to an estimated first and second calibration signal strengths, calculate an I/Q phase imbalance according to an estimated third and fourth calibration signal strengths.

3 more elements

An in-phase/quadrature (I/Q) imbalance calibration method used in a transmitter system operated in an I/Q imbalance calibration mode, comprising:

inputting a first in-phase calibration signal to a front-end circuit of the transmitter system to generate a first calibration signal, acquiring a first calibration signal strength, and estimating the first calibration signal strength by using a delta estimation;
inputting a first quadrature calibration signal to the front-end circuit of the transmitter system to generate a second calibration signal, acquiring a second calibration signal strength, and estimating the second calibration signal strength by using the delta estimation;
calculating an I/Q gain imbalance according to estimated first and second calibration signal strengths;
inputting a second in-phase calibration signal to the front-end circuit of the transmitter system to generate a third calibration signal, acquiring a third calibration signal strength, and estimating the third calibration signal strength by using the delta estimation, wherein an I/Q gain imbalance compensation is formed on the first in-phase calibration signal to generate the second in-phase calibration signal;
inputting both of the second in-phase calibration signal and second quadrature calibration signal to the front-end circuit of the transmitter system to generate a fourth calibration signal, acquiring a fourth calibration signal strength, and estimating the fourth calibration signal strength by using the delta estimation, wherein the I/Q gain imbalance compensation is formed on the first quadrature calibration signal to generate the second quadrature calibration signal;
and
calculating an I/Q phase imbalance according to estimated third and fourth calibration signal strengths.

4 more elements

Dependencies are inferred from the claim text.