Global exponential estimation of the unknown frequencies of discrete-time multi-tone sinusoidal signals

Recently, we studied the problem of estimating the unknown frequencies of discrete-time multi-tone sinusoidal signals. However, the result has two limitations. The first one is that the result is not global and the second one is that the algorithm works only if the constant adaptation gain of the adaptive law is sufficiently small. In this paper, by replacing the constant adaptation gain of our previous design with a time-varying adaptation gain, we overcome the two limitations in our previous result. The advantage of the new design over the existing one is illustrated by numerical simulations. (C) 2022 Elsevier Ltd. All rights reserved.