System and method for compensation of in-phase and quadrature phase and gain imbalance
First Claim
1. A method for correcting phase and gain imbalance errors in synchronous detector including the steps of:
- a) inputting a signal into said detector and extracting therefrom a received signal and a corresponding image signal;
b) inputting said received signal in a first Doppler filter;
c) inputting said image signal in a second Doppler filter;
d) forming a first discriminant g=Re{VT xVI /|VT |2 };
e) forming a second discriminant h=Im{VT xVI /|VT |2 };
where;
VT =the complex voltage output of a target at the output of the first filter andVI =the complex voltage output of an image of the target at the output of the second filter;
computing phase (φ
) and gain (ρ
) errors from the first and second discriminants according to the relationships;
##EQU8## g) calculating first and second correction factors based on said phase and gain errors according to the relationships
space="preserve" listing-type="equation">m=(1+ρ
)/[(1-ρ
) cos (2φ
)]
space="preserve" listing-type="equation">and
space="preserve" listing-type="equation">n=tan (2φ
); and
h) using the correction factors to correct the phase and gain imbalance errors.
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Abstract
A system and method for correcting a gain and phase imbalance between I and Q channels of a synchronous detector. The method of the invention includes the steps of: a) inputting a signal into the detector and extracting therefrom a received signal and a corresponding image signal; b) inputting the received signal in a first Doppler filter; c) inputting the image signal in a second Doppler filter; d) forming a first discriminant; e) forming a second discriminant; f) computing phase (φ) and gain (ρ) errors from the first and second discriminants; g) calculating first and second correction factors based on the phase and gain errors; and h) using the correction factors to correct the phase and gain imbalance errors.
47 Citations
2 Claims
-
1. A method for correcting phase and gain imbalance errors in synchronous detector including the steps of:
-
a) inputting a signal into said detector and extracting therefrom a received signal and a corresponding image signal; b) inputting said received signal in a first Doppler filter; c) inputting said image signal in a second Doppler filter; d) forming a first discriminant g=Re{VT xVI /|VT |2 }; e) forming a second discriminant h=Im{VT xVI /|VT |2 };
where;VT =the complex voltage output of a target at the output of the first filter and VI =the complex voltage output of an image of the target at the output of the second filter; computing phase (φ
) and gain (ρ
) errors from the first and second discriminants according to the relationships;
##EQU8## g) calculating first and second correction factors based on said phase and gain errors according to the relationships
space="preserve" listing-type="equation">m=(1+ρ
)/[(1-ρ
) cos (2φ
)]
space="preserve" listing-type="equation">and
space="preserve" listing-type="equation">n=tan (2φ
); andh) using the correction factors to correct the phase and gain imbalance errors. - View Dependent Claims (2)
-
Specification
-
- Resources
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Current AssigneeHughes Aircraft Company (Rtx Corporation)
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Original AssigneeHughes Aircraft Company (Rtx Corporation)
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InventorsConrad, John C.
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Primary Examiner(s)Barron, Jr., Gilberto
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Application NumberUS07/624,951Time in Patent Office491 DaysField of Search342/174, 342/194US Class Current342/174CPC Class CodesG01S 13/58 Velocity or trajectory dete...G01S 7/352 ReceiversG01S 7/358 using I/Q processingG01S 7/4021 of receiversH03D 1/2245 using two quadrature channe...
