Wideband quadrature error correction
First Claim
1. A transmission system comprising:
- a switch circuit;
a transmitter communicatively coupled to the switch circuit;
a loopback receiver communicatively coupled to the switch circuit;
a calibration circuit communicatively coupled to the switch circuit and configured to output a training data signal; and
a controller communicatively coupled to the loopback receiver and the transmitter,wherein in a first state, the switch circuit is configured to provide a first communication pathway between an output of the calibration circuit and an input of the loopback receiver such that the loopback receiver receives the training data signal and the switch circuit does not provide a second communication pathway between the output of the transmitter and the input of the loopback receiver, and the controller is configured to identify and correct quadrature imbalance in the loopback receiver based at least on a comparison of the output of the loopback receiver with an expected output,wherein in a second state, the switch circuit is configured to provide the second communication pathway between the output of the transmitter and the input of the loopback receiver such that the loopback receiver receives a transmitter-processed data signal and the switch circuit does not provide the first communication pathway between the output of the calibration circuit and the input of the loopback receiver, wherein the transmitter-processed data signal is transmitted by the transmitter, and the controller is configured to;
identify quadrature imbalance in the transmitter based at least in part on a comparison of a loopback receiver-processed data signal received from the loopback receiver with a buffered data signal that corresponds to the transmitter-processed data signal prior to being processed and transmitted by the transmitter, wherein the loopback receiver-processed data signal and the buffered data signal each comprise an in-phase data signal and a quadrature data signal, andadjust one or more characteristics of the transmitter to correct the identified quadrature imbalance present in the transmitter based at least in part on the comparison.
1 Assignment
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Accused Products
Abstract
A transmission module is provided that includes a transmitter, a loopback receiver, and a QEC controller. In a first state, the QEC controller calibrates the loopback receiver to remove quadrature imbalance in the loopback receiver. In a second state, a communication pathway is provided between the transmitter and the loopback receiver, and the QEC controller identifies quadrature imbalance in the transmitter based at least one a comparison of the data signals at the output of the loopback receiver with data signals at the input of the transmitter. Based on the comparison, the QEC controller can adjust one or more characteristics of the transmitter to correct quadrature errors in the transmitter.
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Citations
19 Claims
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1. A transmission system comprising:
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a switch circuit; a transmitter communicatively coupled to the switch circuit; a loopback receiver communicatively coupled to the switch circuit; a calibration circuit communicatively coupled to the switch circuit and configured to output a training data signal; and a controller communicatively coupled to the loopback receiver and the transmitter, wherein in a first state, the switch circuit is configured to provide a first communication pathway between an output of the calibration circuit and an input of the loopback receiver such that the loopback receiver receives the training data signal and the switch circuit does not provide a second communication pathway between the output of the transmitter and the input of the loopback receiver, and the controller is configured to identify and correct quadrature imbalance in the loopback receiver based at least on a comparison of the output of the loopback receiver with an expected output, wherein in a second state, the switch circuit is configured to provide the second communication pathway between the output of the transmitter and the input of the loopback receiver such that the loopback receiver receives a transmitter-processed data signal and the switch circuit does not provide the first communication pathway between the output of the calibration circuit and the input of the loopback receiver, wherein the transmitter-processed data signal is transmitted by the transmitter, and the controller is configured to; identify quadrature imbalance in the transmitter based at least in part on a comparison of a loopback receiver-processed data signal received from the loopback receiver with a buffered data signal that corresponds to the transmitter-processed data signal prior to being processed and transmitted by the transmitter, wherein the loopback receiver-processed data signal and the buffered data signal each comprise an in-phase data signal and a quadrature data signal, and adjust one or more characteristics of the transmitter to correct the identified quadrature imbalance present in the transmitter based at least in part on the comparison.
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2. A transmission system comprising:
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a transmitter; a loopback receiver; and a controller configured to; in a first mode, calibrate the loopback receiver to account for quadrature imbalance in the loopback receiver, wherein in the first mode, a switch circuit provides a first communication pathway between an output of a calibration circuit and an input of the loopback receiver such that the loopback receiver receives a training data signal and the switch circuit does not provide a second communication pathway between an output of the transmitter and the input of the loopback receiver, and in a second mode; receive a loopback receiver-processed data signal from the calibrated loopback receiver that corresponds to a transmitter-processed data signal that is processed by the receiver, identify quadrature imbalance in the transmitter based at least in part on a comparison of the loopback receiver-processed data signal received from the calibrated loopback receiver with a buffered data signal that corresponds to the transmitter-processed data signal prior to being processed by the transmitter, wherein the loopback receiver-processed data signal and the buffered data signal each comprise an in-phase data signal and a quadrature data signal, and adjust at least one of one or more filters or one or more long oscillation delays of the transmitter to correct the identified quadrature imbalance based at least in part on the comparison, wherein in the second mode, the switch circuit provides a second communication pathway between an output of the transmitter and the input of the loopback receiver such that the loopback receiver receives a transmitter-processed data signal and the switch circuit does not provide the first communication pathway between the output of the calibration circuit and the input of the loopback receiver. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An electronically-implemented method for quadrature error correction comprising:
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in a first mode, calibrating a loopback receiver to account for quadrature imbalance in the loopback receiver, wherein in the first mode, a switch circuit provides a first communication pathway between an output of a calibration circuit and an input of a loopback receiver such that the loopback receiver receives a training data signal and the switch circuit does not provide a second communication pathway between an output of a transmitter and the input of the loopback receiver; and in a second mode; receiving, from the calibrated loopback receiver, a loopback receiver-processed data signal that corresponds to a transmitter-processed data signal that has been processed by the calibrated loopback receiver; identifying quadrature imbalance in the transmitter based at least in part on a comparison of the loopback receiver-processed data signal received from the calibrated loopback receiver with a buffered data signal that corresponds to the transmitter-processed data signal prior to being processed by the transmitter, wherein the loopback receiver-processed data signal and the buffered data signal each comprise an in-phase data signal and a quadrature data signal; and adjusting one or more characteristics of the transmitter to correct the identified quadrature imbalance based at least in part on the comparison, wherein in the second mode, the switch circuit provides a second communication pathway between the output of the transmitter and the input of the loopback receiver such that the loopback receiver receives a transmitter-processed data signal and the switch circuit does not provide the first communication pathway between the output of the calibration circuit and the input of the loopback receiver. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification