Abstract: A system and method for detecting antenna coupling and for providing feedback cancellation in response to the antenna coupling includes a signal feedback cancellation circuit configured to be coupled between a signal receiver and a signal transmitter. The feedback cancellation circuit is responsive to received signals, amplified signals and the detection of signal coupling between a receiving antenna any transmitting antenna, for providing a feedback cancellation signal to a signal amplifier. The feedback cancellation circuit may employ time domain or frequency domain methods. In the case of a time domain method, the feedback cancellation circuit may further include a White noise generator which serves to the tune or adjust the feedback cancellation circuit.
Abstract: A method for controlling an adjustable gain in an amplifier having an output power level and an adjustable gain is disclosed. The method includes an enhancement to a conventional Automatic Gain Control (AGC) function that distinguishes between a signal caused by oscillation and a signal that actually appears in the amplifier's passband. The method also controls unwanted and out of control amplifier oscillation using an iterative correlation process. The method prevents gain “hunting” if the output signal level is near the “set point” of the maximum permitted output level by implementing some degree of Hysteresis. The correlation process is performed by tracking a specified number of alternating gain increase/decrease cycles. If in any cycle the gain is not changed, or is changed in the same direction as in the previous cycle, the correlator is reset and the process begins again.