DUAL-LOOP TRANSMIT NOISE CANCELLATION

摘要

A transmitter circuit is described. The transmitter circuit includes a first local oscillator that generates a first frequency equal to a duplex frequency. The transmitter circuit also includes a second local oscillator that generates a second frequency equal to a receive frequency. The transmitter circuit further includes a first mixer that combines the first frequency with a first input signal. The transmitter circuit also includes a first feedback loop. The first feedback loop includes a second mixer that combines the second frequency with a transmit signal and a first filter and a first adder that combines an output of the first mixer with an output of the first filter. The transmitter circuit also includes a third local oscillator that generates a third frequency equal to the receive frequency. The transmitter circuit further includes a third mixer that combines the third frequency with an output of the first adder.

主权项

1. A method for noise cancellation in a transmit signal, the method comprising:
estimate transmit noise in the transmit signal that negatively affects a receive signal; estimate transmit distortion in the transmit signal that negatively affects the fidelity of the transmit signal; filter estimated transmit noise from the transmit signal; filter estimated transmit distortion from the transmit signal; and provide a filtered transmit signal to a duplexer.