Averaging analysis of local stability of a real constant modulus algorithm adaptive filter

The constant modulus algorithm (CMA) of adaptive filtering was developed for usage when the modulus of the desired signal is known, but its specific value at every sample instant is not known. A real-arithmetic version of CMA was recently proposed, and studied using simulations, by J.R. Treichler and M.G. Larimore (ibid., vol.ASSP-33, p.420-31, Apr. 1985). Local stability of their arithmetic version of CMA is proven in two applications: channel equalization for a transmitted sequence of plus and minus ones, and the separation of a sinusoidal signal from its sum with a number of sinusoidal interferers at separate frequencies. The proofs utilize dynamic system stability theorems from averaging theory, which is a technique currently being utilized in the stability analysis of a variety of adaptive systems. >