Patent ID: 6704349
Filing Date: 2004-03-09
Classification: H04B

Abstract:
An adaptive coherent digital canceller system configured to attenuate a transmitter leakage signal spectrum that leaks into a bandwidth of a receiver, the canceller system comprising:a reference filter filtering a transmit signal from a transmitter, the reference filter having a transfer function substantially similar to a receiver filter adapted to filter a received signal; a reference direct converter receiving a filtered signal from the reference filter, the reference direct converter adapted to output a digitized transmit signal reference of a spectral energy of the transmitter within the bandwidth of the receiver, the digitized transmit signal having a phase and an amplitude; a cross correlation measurer receiving an output signal from the reference direct converter, the cross correlation measurer cross-correlating a first signal from a receiver path with a second signal from the reference direct converter, the cross correlation measurer identifying common signal characteristics of the first and second signals; an adaptation coherent spectral canceller module receiving parameters from the cross correlation measurer; an adaptive digital transversal filter receiving an output signal from the reference direct converter and receiving coefficients from the canceller module, the transversal filter aligning the amplitude and phase of the output signal from the reference direct converter with the transmitter leakage signal spectrum in the receiver path, the adaptive digital transversal filter outputting a compensated digitized transmit signal reference; and a combiner adapted to coherently subtract the compensated digitized transmit signal reference from the receiver signal with the transmitter leakage signal spectrum to form a residue whose transmitter spectral signal power within the bandwidth of the receiver is suppressed.