All digital transmitter noise correction

摘要

An all digital model of nonlinear transmitter signal distortion in signals received at a receiver of a transmitter-receiver may be used to estimate distortion. The estimated distortion may then be cancelled from the received signals to improve signal quality of the received signal. The digital nonlinear model may be part of an estimator circuit that estimates nonlinear distortion terms by applying a formula or transformation to a digitized version of the signals transmitter at a transmitter of the transmitter-receiver. A mixer may be used to shift a frequency of the estimated nonlinear terms away from a transmitter frequency so that the nonlinear terms can later be subtracted from the incoming signal received at the receiver at a receiver frequency. Circuits and methods are provided.

主权项

1. A circuit comprising:
an estimator circuit modeling nonlinear signal distortion from a transmitter at a receiver based on an analysis of an outgoing digital signal converted to an analog signal and transmitted at the transmitter; a mixer mixing an output of the estimator circuit with a frequency offset signal and shifting the estimator circuit output to an intermediate frequency offset representing a difference between frequencies of the transmitter and the receiver; and a subtractor coupled to the mixer and subtracting the frequency shifted estimator circuit output from a digitized incoming signal received at the receiver; a delay unit delaying the estimator circuit output until the estimator circuit output is synchronized with a corresponding portion of the incoming signal at the subtractor; and a decimator downsampling the mixed estimator circuit output to a frequency of the incoming signal before the subtractor subtracts the downsampled estimator output from the incoming signal.