Efficient algorithms for the generation of noise samples are required for the software simulation of radar systems. In many cases, such as the modelling of oscillator phase noise, noise samples with a power spectral density (PSD) that match an fα model are required. An algorithm for the generation of sequences of fα noise samples, based on a multirate filterbank is presented. A technique for pruning of the multirate filterbank, allowing highly efficient generation of pulsed sequences of fα noise samples while preserving long term correlations, is also presented, as well as a noise generation algorithm designed to model the phase noise of precision oscillators.