Concurrent Dual-Band RF Signal Measurement With Adaptive Blind Feedforward Cancellation of Wideband Receiver Nonlinearities

This paper proposes a novel method for the digital blind cancellation of nonlinear distortion in the concurrent dual-band receiver, for the accurate acquisition and testing of dual-band radio frequency signal. The nonlinearities are incurred by the wideband low-noise amplifier when measuring two signals concurrently. The proposed blind algorithm extracts the nonlinearities in the two measured signals and then cancels out the nonlinear distortion by subtracting it from the two signals, using a feedforward scheme iteratively [blind feedforward cancellation (BFFC)], based on the state-of-the-art 2-D memoryless polynomial model. An extended application by reducing the model complexity using the 2-D modified memoryless polynomial model has also been evaluated to be effective. Experimental results have shown that the proposed method eliminates the nonlinearities in the dual-band and improves the signal quality significantly. The convergence behavior of the BFFC technique is further augmented by using a general iterative equation. All the results have been compared with the previous blind postcompensation methods and the results demonstrate the superiority of the new method.