Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
70 words
A method for calibrating a data receiver to correct for errors inherent in the receiver, characterised in that it comprises the steps of: measuring at least one characteristic of received data signals and fitting the measured characteristic to a linearly transformed model; determining transformation parameters which describe the model; relating each determined parameter to a calibration factor; and applying said calibration factors to the received data to produce corrected data.
Claim 2
Independent Claim
70 words
A method for calibrating a data receiver to correct for errors inherent in the receiver, characterised in that it comprises the steps of: measuring at least one characteristic of received data signals and fitting the measured characteristic to a linearly transformed model; determining transformation parameters which describe the model; relating each determined parameter to a calibration factor; and applying said calibration factors to the received data to produce corrected data.
Claim 3
Dependent Claim
70 words
The method of claim 1 wherein the data receiver is a vector demodulator; the measured characteristic of the data signal is the magnitude of in-phase (I) and quadrature (Q) components, measured at points in time to define coordinate pairs of values (I,Q); said model is a linearly transformed model defined by the coordinate pairs of values (I,Q); and said calibration factor is an error that can occur in the demodulator.
Claim 4
Dependent Claim
29 words
The method of claim 1 or 2 wherein the model is an ellipse defined by the parameters; center(E), ratio of principal axes (22,24), skew of principal axes⊖, and scale.
Claim 5
Dependent Claim
37 words
The method of claim 3 wherein said parameters are respectively associated with the errors; DC offset in the in-phase (I) and quadrature channels (Q) of the demodulator, gain imbalance between the channels, quadrature error, and amplification gain.
Claim 6
Independent Claim
14 words
The method of any preceding claim wherein the parameters are determined by regression analysis.
Claim 7
Dependent Claim
14 words
The method of claim 5 wherein the regression analysis comprises nonlinear least squares analysis.
Claim 8
Independent Claim
32 words
The method of any claim from 2 to 4 wherein the parameters are determined by robust regression analysis in which the coordinate pairs of (I,Q) values are weighted to reject aberrant values.
Claim 9
Dependent Claim
17 words
The method of claim 7 wherein the robust regression analysis comprises iteratively reweighted nonlinear least squares analysis.
Claim 10
Independent Claim
20 words
The method of any preceding claim further including the step of calculating a range of certainty for each determined parameter.