Importance

Loading Importance Indicators...

Abstract

A method for compensating for time mismatch between an interference signal path and a cancellation signal path in an interference cancellation system involves two cross correlation steps. The first cross correlation establishes a baseline by correlating a reference signal at a synchronous detector of the interference cancellation system with a reference signal through a signal controller and error signal path of the system, which is the signal route from a sample coupler of the interference cancellation system to the synchronous detector by which the residual cancellation signal is measured. When this process is taking place, external signals from the air path are eliminated by using an isolation switch in the receive signal path of a radio receiver system to which the interference cancellation system is coupled. The second correlation is performed between the reference signal at the synchronous detector and the external interference through the error signal path. This process is accomplished with the signal controller set to maximum attenuation and the isolation switch in the low loss state. Using the correlation results, the time mismatch can be found by comparing the position of the correlation nulls between the two correlation responses. The time difference between the correlation nulls corresponds directly to the time match between the two propagation paths. The cross correlations are performed by a signal correlator forming part of an interference cancellation system.

Loading the Abstract Image...

First Claim