Patent ID: 7197087

Claim:
A method for compensating for a relative time delay between an in-phase and quadrature signal paths of a communications system utilizing an analog quadrature modulator, wherein the communications system comprises a forward path and an observation path, comprising: digitally computing timing errors for the in-phase and quadrature signal paths, comprising: computing a timing error for the in-phase signal path from the difference between a cross-correlation of an in-phase part of a forward path signal with a delayed in-phase part of an observation path signal and the cross-correlation of the in-phase part of the forward path signal with an advanced in-phase part of the observation path signal, and computing a timing error for the quadrature signal path from the difference between a cross-correlation of a quadrature part of a forward path signal with a delayed quadrature part of the observation path signal and the cross-correlation of the quadrature part of the forward path signal with an advanced quadrature part of the observation path signal; and adjusting one or both of the forward path in-phase and quadrature signal paths to remove the relative time delay between the in-phase and quadrature signal paths.