According to one embodiment taught herein, a method of determining impairment correlations between a plurality of delays of interest for a received CDMA signal comprises generating kernel functions as samples of a net channel response of the received CDMA signal taken at defined chip sampling phases for delay differences between the plurality of delays of interest. In a parametric Generalized Rake (G-Rake) receiver embodiment, the delays of interest represent the delay positions of the fingers being used to characterized received signal. In a chip equalizer receiver embodiment, the delays of interest represent the delay positions of the equalizer taps. The method continues with determining impairment correlations based on convolving the kernel functions. Corresponding receiver circuits, including an impairment correlation estimation circuit configured for parametric G-Rake operation, may be implemented in a variety of communication devices and systems, such as in wireless communication network base stations and mobile stations.