System and method for feedback cancellation in repeaters

A circuit for reducing the effect of feedback signals in a repeater apparatus that repeats input signals received by a receive antenna and transmits the repeated signals with a transmit antenna, the circuit comprising:

• an adaptive digital filter configured to generate cancellation signals to be added to input signals to attenuate unwanted signals in the input signals, the cancellation signals configured to cancel feedback signals received by the repeater apparatus along with the input signals;
• a frequency shifting circuit configured for adding a frequency shift to the repeated signals to form repeated signals that are frequency shifted from the input signals;
• a digital signal processor coupled to the adaptive digital filter and operable for adapting the filter;
• the digital signal processor configured for utilizing the frequency shift of the repeated signals to adapt the adaptive digital filter.

A method of repeating signals comprising:

• receiving input signals;
• processing the input signals to form repeated signals;
• transmitting the repeated signals;
• the processing of the input signals including:
• generating cancellation signals with an adaptive digital filter and adding the cancellation signals to the input signals to attenuate feedback signals in the input signals;
• adding a frequency shift to the input signals to form repeated signals that are frequency shifted from the input signals;
• utilizing the frequency shift of the transmission signals to adjust the adaptive digital filter.