Abstract: An interference cancellation system for cancelling interfering signals which is adapted to be connected to a radio receiver system having a receiver antenna, a receiver and a receiver transmission line interconnecting the receiver antenna and the receiver includes an auxiliary antenna, a first directional coupler connected to the auxiliary antenna, a second directional coupler or error coupler connected to the receiver transmission line, a synchronous detector connected to the first and second directional couplers, a vector rotator connected to the outputs of the synchronous detector, a signal controller connected to the vector rotator and a third directional coupler or summer coupler connected to the receiver transmission line and to the signal controller. The vector rotator enables the internal time match of the cancellation system to be optimized by quadrature positioning by varying resistor values in the vector rotator circuit.

Abstract: An interference cancellation system employing a polar vector modulator obtains a reference signal and a received signal. The received signal has a desired signal component and an interfering signal component. The reference and received signals as well as an auxiliary signal of known frequency and amplitude, are provided to a signal correlator circuit which compares and correlates the reference and received signals and generates an adjusted auxiliary signal which corresponds to the auxiliary signal adjusted in phase and amplitude. A phase detector detects the difference in phase between the auxiliary signal and the adjusted auxiliary signal and generates a phase control signal in response. Likewise, an amplitude detector measures the amplitude of the adjusted auxiliary signal and generates an amplitude control signal in response. The phase and amplitude control signals and the reference signal are provided to a polar vector modulator having a 360.degree.

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.