Communications device with in-phase/quadrature (I/Q) DC offset, gain and phase imbalance compensation and related method

摘要

A DC offset estimator and removal circuit removes the DC offsets for each of the I and Q signal components in a received signal. A gain imbalance estimator and compensator circuit estimates and compensates for gain imbalances within the I and Q signal components. A phase imbalance estimator and compensator circuit estimates and compensates for phase imbalances within the I and Q signal components to produce a communications signal that is compensated for received DC offsets and gain and phase imbalances within the I and Q signal components.

主权项

1. A method of processing a communications signal having communications data, comprising:
receiving within a radio receiver a radio frequency (RF) communications signal; performing a Quadrature demodulation of the communications signal to another intermediate frequency and producing In-phase (I) and Quadrature (Q) signal components; sampling the signal components to obtain input samples; estimating DC offsets for each of the I and Q signal components by estimating an average over “n” samples, wherein n is an odd number greater than 1, and subtracting the average only from a middle sample and repeating a plurality of times based on a sliding window calculation the estimating of an average over “n” samples while subtracting the average only from the middle sample to form an average estimate and updating this average estimate by adding a newly received sample to the average and subtracting off a stored sample delayed by sample periods and removing the updated average estimate of the DC offset from each of the I and Q signal components, followed by; estimating and compensating for gain imbalances within the I and Q signal components; and estimating and compensating for phase imbalances within the I and Q signal components to produce a communications signal.