quin2

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function [x] = quin2(Y)  % Adapted by Eric Jacobsen, June, 2002. % % Y is a three-element complex vector with the % DFT output magnitude maximizer as the center element. %  % Returns -0.5 < x < 0.5, which is the fraction of the sample % spacing (i.e., bin width) about the center element where the % peak is estimated to be. % % Ref: Quinn, BG, "Estimation of frequency, amplitude and phase % from the DFT of a time series," IEEE Trans. Sig. Proc. Vol 45, No 3, % Mar 1997, pp814-817.   betam=real(Y(1)/Y(2)); betap=real(Y(3)/Y(2));  dm=-betam/(betam-1); dp= betap/(betap-1);  kappap=(1/4)*log(3*(dp^4)+6*(dp^2)+1) - (sqrt(6)/24)*log(((dp^2)+1-sqrt(2/3))/((dp^2)+1+sqrt(2/3))); kappam=(1/4)*log(3*(dm^4)+6*(dm^2)+1) - (sqrt(6)/24)*log(((dm^2)+1-sqrt(2/3))/((dm^2)+1+sqrt(2/3)));  delta=(dm+dp)/2 +kappap-kappam;  x=delta;  %